A university found that 20% of its students withdraw without completing the introductory statistics course. Assume that 20 students registered for the course. (a) Compute the probability that 2 or fewer will withdraw. If required, round your answer to four decimal places. (b) Compute the probability that exactly 4 will withdraw. If required, round your answer to four decimal places. (c) Compute the probability that more than 3 will withdraw. If required, round your answer to four decimal places. (d) Compute the expected number of withdrawals.

Answers

Answer 1

Answer:

a) 0.206 = 20.6% probability that 2 or fewer will withdraw.

b) 0.2182 = 21.82% probability that exactly 4 will withdraw.

c) 0.5886 = 58.86% probability that more than 3 will withdraw.

d) The expected number of withdrawals is 4.

Step-by-step explanation:

For each student, there are only two possible outcomes. Either they withdraw without completing the introductory statistics course, or they do not. Each student is independent of each other. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

In which [tex]C_{n,x}[/tex] is the number of different combinations of x objects from a set of n elements, given by the following formula.

[tex]C_{n,x} = \frac{n!}{x!(n-x)!}[/tex]

And p is the probability of X happening.

20% of its students withdraw without completing the introductory statistics course.

This means that [tex]p = 0.2[/tex]

Assume that 20 students registered for the course.

This means that [tex]n = 20[/tex]

(a) Compute the probability that 2 or fewer will withdraw.

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2)[/tex]

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{20,0}.(0.2)^{0}.(0.8)^{20} = 0.0115[/tex]

[tex]P(X = 1) = C_{20,1}.(0.2)^{1}.(0.8)^{19} = 0.0576[/tex]

[tex]P(X = 2) = C_{20,2}.(0.2)^{2}.(0.8)^{18} = 0.1369[/tex]

[tex]P(X \leq 2) = P(X = 0) + P(X = 1) + P(X = 2) = 0.0115 + 0.0576 + 0.1369 = 0.206[/tex]

0.206 = 20.6% probability that 2 or fewer will withdraw.

(b) Compute the probability that exactly 4 will withdraw.

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 4) = C_{20,4}.(0.2)^{4}.(0.8)^{16} = 0.2182[/tex]

0.2182 = 21.82% probability that exactly 4 will withdraw.

(c) Compute the probability that more than 3 will withdraw.

Either less than 3 withdraw, or more than 3 withdraw. The sum of the probabilities of these events is 1. So

[tex]P(X \leq 3) + P(X > 3) = 1[/tex]

We want P(X > 3). So

[tex]P(X > 3) = 1 - P(X \leq 3)[/tex]

In which

[tex]P(X \leq 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3)[/tex]

[tex]P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}[/tex]

[tex]P(X = 0) = C_{20,0}.(0.2)^{0}.(0.8)^{20} = 0.0115[/tex]

[tex]P(X = 1) = C_{20,1}.(0.2)^{1}.(0.8)^{19} = 0.0576[/tex]

[tex]P(X = 2) = C_{20,2}.(0.2)^{2}.(0.8)^{18} = 0.1369[/tex]

[tex]P(X = 3) = C_{20,3}.(0.2)^{3}.(0.8)^{17} = 0.2054[/tex]

[tex]P(X \leq 3) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) = 0.0115 + 0.0576 + 0.1369 + 0.2054 = 0.4114[/tex]

[tex]P(X > 3) = 1 - P(X \leq 3) = 1 - 0.4114 = 0.5886[/tex]

0.5886 = 58.86% probability that more than 3 will withdraw.

(d) Compute the expected number of withdrawals.

The expected value of the binomial distribution is:

E(X) = np

In this question:

E(X) = 20*0.2 = 4

The expected number of withdrawals is 4.


Related Questions

Find the exact value of cos 15º.

Answers

Answer:

0.965925826

Step-by-step explanation:

Answer:

(pi6 + pi2)/4

Step-by-step explanation:

A water storage tank has a cylindrical shape. The base has a diameter of
15 meters and the tank is 30 meters high. How much paint will be needed to cover the outside
of the tank, to the nearest meter squared unit?

Answers

Answer:

1761 square meters

Step-by-step explanation:no, thanks.

A loan company charges $30 interest <br />for a one month loan of $500. Find the annual interest they are charging ​

Answers

Answer:

$360

Step-by-step explanation:

If the company charges $30 for $500 in one month.

The interest they will be changing for a year = 30*12 = $360 interest.

It's just simple, multipling the the interest value by 12 to get it's annual interest value.

Write the statement as a proportion. Name the means and the extremes: a.2isto3as8isto12 b. 90isto36 as135isto54

Answers

Answer:

Step-by-step explanation:

A certain daily delivery route for Hostess breads and snack cakes includes eight grocery stores and four convenience stores. The historical mean tome to complete these deliveries (to the 12 stores) and return to the distribution center is 6.5 hours. A new deliver has been assigned to this route, and a random sample of his route completion times (in hours) was obtained. The data are given below:

6.61, 6.25, 6.40, 6.57, 6.35, 5.95, 6.53, 6.29

Required:
Assume the underlying population is normal. Is there evidence to suggest that the new driver has been able to shorten the route completion time, at the level of significance 0.01?

a. 0.05 b. 0.1 < p-value < 0.2: There is no evidence to suggest tha tthe new driver has been able to shorten the mean delivery time for this route.
c. 0.1 < p-value < 0.2: There is an enough evidence to suggest thatthe new driver has been able to shorten the mean delivery time for this route.
d. 0.05 < p-value < 0.1: There is no evidence to suggest tha tthe new driver has been able to shorten the mean delivery time for this route.

Answers

Answer:

d. 0.05 < p-value < 0.1: There is no evidence to suggest tha tthe new driver has been able to shorten the mean delivery time for this route.

Step-by-step explanation:

We calculate the mean and standard deviation of the sample:

[tex]M=\dfrac{1}{8}\sum_{i=1}^{8}(6.61+6.25+6.4+6.57+6.35+5.95+6.53+6.29)\\\\\\ M=\dfrac{50.95}{8}=6.369[/tex]

[tex]s=\sqrt{\dfrac{1}{(n-1)}\sum_{i=1}^{8}(x_i-M)^2}\\\\\\s=\sqrt{\dfrac{1}{7}\cdot [(6.61-(6.369))^2+...+(6.29-(6.369))^2]}\\\\\\s=\sqrt{\dfrac{0.3216875}{7}}=\sqrt{0.046}\\\\\\s=0.214[/tex]

This is a hypothesis test for the population mean.

The claim is that the new driver has been able to shorten the route completion time (significantly less than 6.5 hours).

Then, the null and alternative hypothesis are:

[tex]H_0: \mu=6.5\\\\H_a:\mu< 6.5[/tex]

The significance level is 0.01.

The sample has a size n=8.

The sample mean is M=6.369.

As the standard deviation of the population is not known, we estimate it with the sample standard deviation, that has a value of s=0.214.

The estimated standard error of the mean is computed using the formula:

[tex]s_M=\dfrac{s}{\sqrt{n}}=\dfrac{0.214}{\sqrt{8}}=0.08[/tex]

Then, we can calculate the t-statistic as:

[tex]t=\dfrac{M-\mu}{s/\sqrt{n}}=\dfrac{6.369-6.5}{0.08}=\dfrac{-0.13}{0.08}=-1.73[/tex]

The degrees of freedom for this sample size are:

[tex]df=n-1=8-1=7[/tex]

This test is a left-tailed test, with 7 degrees of freedom and t=-1.73, so the P-value for this test is calculated as (using a t-table):

[tex]P-value=P(t<-1.73)=0.063[/tex]

As the P-value (0.063) is bigger than the significance level (0.01), the effect is  not significant.

The null hypothesis failed to be rejected.

There is not enough evidence to support the claim that the new driver has been able to shorten the route completion time (significantly less than 6.5 hours).

Bob collects stamps. Each day he adds 4 stamps to his collection. At the end of three days he has 50 stamps. How many stamps does he have at the end of 10 days? *

Answers

Answer:

78 stamps

Step-by-step explanation:

50 stamps collected after 3 days

4 stamps added a day

next 7 days added= 7*4= 28 stamps

Total after 10 days= 50+28= 78 stamps

You do a study of hypnotherapy to determine how effective it is in increasing the number of hours of sleep subjects get each night. You measure hours of sleep for 12 subjects with the following results. Construct a 95% confidence interval for the mean number of hours slept for the population (assumed normal) from which you took the data AND determine the margin of error EBM.

DATA: 8.2; 9.1; 7.7; 8.6; 6.9; 11.2; 10.1; 9.9; 8.9; 9.2; 7.5; 10.5

Answers

Answer:

Confidence interval

[tex]8.98-2.2\frac{1.29}{\sqrt{12}}=8.16[/tex]    

[tex]8.98+2.2\frac{1.29}{\sqrt{12}}=9.80[/tex]  

And the margin of error would be:

[tex] ME=2.2\frac{1.29}{\sqrt{12}}=0.819[/tex]

Step-by-step explanation:

For this case we have the followig dataset:

DATA: 8.2; 9.1; 7.7; 8.6; 6.9; 11.2; 10.1; 9.9; 8.9; 9.2; 7.5; 10.5

We can calculate the mean and the deviation with the following formulas:

[tex]\bar X = \frac{\sum_{i=1}^n X_i}{n}[/tex]

[tex]s =\sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}[/tex]

And replacing we got:

[tex] \bar X= 8.98[/tex

[tex]s = 1.29[/tex]

The confidence interval for the mean is given by the following formula:

[tex]\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}[/tex]   (1)

The degrees of freedom are given by:

[tex]df=n-1=12-1=11[/tex]

The Confidence level is 0.95 or 95%, the value of significance is [tex]\alpha=0.05[/tex] and [tex]\alpha/2 =0.025[/tex], and the critical value would be [tex]t_{\alpha/2}=2.20[/tex]

Repplacing the info we got:

[tex]8.98-2.2\frac{1.29}{\sqrt{12}}=8.16[/tex]    

[tex]8.98+2.2\frac{1.29}{\sqrt{12}}=9.80[/tex]    And the margin of error would be:

[tex] ME=2.2\frac{1.29}{\sqrt{12}}=0.819[/tex]

The 95% confidence interval is [tex]\mathbf{ (8.17,9.79)}[/tex], and the margin of error is 0.81

The dataset is given as:

[tex]\mathbf{x= 8.2; 9.1; 7.7; 8.6; 6.9; 11.2; 10.1; 9.9; 8.9; 9.2; 7.5; 10.5}[/tex]

Start by calculating the sample mean

This is calculated as:

[tex]\mathbf{\bar x = \frac{\sum x}{n}}[/tex]

[tex]\mathbf{\bar x= \frac{8.2+ 9.1+ 7.7+ 8.6+ 6.9+11.2+ 10.1+ 9.9+ 8.9+ 9.2+ 7.5+ 10.5}{12}}[/tex]

[tex]\mathbf{\bar x= \frac{107.8}{12}}[/tex]

[tex]\mathbf{\bar x= 8.98}[/tex]

Next, calculate the sample standard deviation

This is calculated as:

[tex]\mathbf{\sigma_x = \sqrt{\frac{\sum (x - \bar x)^2}{n-1}}}[/tex]

[tex]\mathbf{\sigma_x= \sqrt{\frac{(8.2 - 8.89)^2 +.......... + (10.5- 8.89)^2}{12 - 1}}}[/tex]

[tex]\mathbf{\sigma_x= 1.29}[/tex]

Calculate the degrees of freedom

[tex]\mathbf{df = n - 1}[/tex]

[tex]\mathbf{df = 12 - 1}[/tex]

[tex]\mathbf{df = 11}[/tex]

Calculate the significance level

[tex]\mathbf{\alpha /2=\frac{1 - 95\%}2 = 0.025}[/tex]

The critical value at [tex]\mathbf{\alpha/2 = 0.025}[/tex]  and df = 11 is:

[tex]\mathbf{t_{\alpha/2} = 2.20}[/tex]

Calculate the margin of error

[tex]\mathbf{E = t_{\alpha/2} \frac{\sigma}{\sqrt n}}[/tex]

So, we have:

[tex]\mathbf{E = 2.20 \times \frac{1.29}{\sqrt{12}}}[/tex]

[tex]\mathbf{E = 0.81}[/tex]

The confidence interval is then calculated as:

[tex]\mathbf{CI =\bar x \pm E}[/tex]

So, we have:

[tex]\mathbf{CI = 8.98 \pm 0.81}}[/tex]

Split

[tex]\mathbf{CI = (8.98 - 0.81,8.98 + 0.81)}[/tex]

[tex]\mathbf{CI = (8.17,9.79)}[/tex]

So, the 95% confidence interval is [tex]\mathbf{ (8.17,9.79)}[/tex], and the margin of error is 0.81

Read more about confidence intervals and margin of errors at:

https://brainly.com/question/19426829

Which orderd pair is a solution of the equation-3x+5y = 2x + 3y

Answers

Answer:

2y=5x

Step-by-step explanation:

-3x+5y=2x+3y

5y=5x+3y

2y=5x

3. The path of an underground stream is given by the function y = 4x² +17x -32. Two

new houses need wells to be dug. On the area plan, these houses lie on a line defined by

the equation y = –15x+10. Determine the coordinates where the two wells need to be

dug.

Answers

Answer:

The coordinate of the wells are

[tex] (-4 -\sqrt[]{\frac{53}{2}}, 70+15\sqrt[]{\frac{53}{2}})[/tex]

[tex] (-4 +\sqrt[]{\frac{53}{2}}, 70-15\sqrt[]{\frac{53}{2}})[/tex]

Step-by-step explanation:

The y coordinate of the stream is given by [tex] y = 4x^2+17x-32[/tex]. Also, the y coordinate of the houses are determined by y=-15x+10. We will assume that the houses are goint to be built on the exact position where we build the wells. We want to build the wells at the exat position in which both functions cross each other, so we have the following equation

[tex] 4x^2+17x-32 = -15x+10[/tex]

or equivalently

[tex]4x^2+32x-42=0[/tex] (by summing 15x and substracting 10 on both sides)

Dividing by 2 on both sides, we get

[tex]2x^2+16x-21=0[/tex]

Recall that given the equation of the form [tex]ax^2+bx+c=0[/tex] the solutions are

[tex] x = \frac{-b \pm \sqrt[]{b^2-4ac}}{2a}[/tex]

Taking a =2, b = 16 and c = -21, we get the solutions

[tex]x_1 = -4 -\sqrt[]{\frac{53}{2}}[/tex]

[tex]x_2 = -4 +\sqrt[]{\frac{53}{2}}[/tex]

If we replace this values in any of the equations, we get

[tex]y_1 = 70+15\sqrt[]{\frac{53}{2}}[/tex]

[tex]y_2 = 70-15\sqrt[]{\frac{53}{2}}[/tex]

An isotope with a mass number of 193 has 116 neutrons. What is the atomic number of this isotope?

Answers

Answer:

Yttrium

Step-by-step explanation:

The atomic number of yttrium is 39. . An isotope with an atomic mass of 193 has 116 neutrons.

Answer:

77

number of protons is 77. Therefore atomic number atomic number is 77.

hey! could you help me answer these questions? i really need them quick! i’ll mark u as the brainliest

Answers

Answer:

Hope this is correct

In order to accurately estimate the difference between the number of touchdowns scored by the Detroit Lions and the Seattle Seahawks in a particular string of n = 5 games, we must know that the standard deviations for the two teams are equal. Suppose that in this string of games the Lions score an average of x_1 = 2 touchdowns per game with a standard deviation of s_1 = 0.37, while the Seahawks score an average of x_2 = 2.8 touchdowns with standard deviation s_2 = 1.89. Can we assume, at the alpha = 0.1 significance level, that the standard deviations for these two teams are the same? a) Test Statistic: b) Critical Value: c) Conclusion: A. There is sufficient evidence to conclude that the standard deviations are different. B. There is insufficient evidence to conclude the standard deviations are different. We may assume they are equal.

Answers

Answer:

Step-by-step explanation:

Here,

[tex]H_0:\sigma _1 = \sigma _2\\\\H_1:\sigma_1 \neq \sigma_2[/tex]

a) Test Statistic

[tex]F = \frac{S_1^2}{S_1^2} \\\\=\frac{0.37^2}{1,89^2} \\\\=0.04[/tex]

b) Critical value for

[tex]\sigma = 0.1[/tex]

degrees of freedom is

[tex](n_1 - 1, n_2 -1)[/tex]

d.f =(5 - 1, 5 - 1)

d.f = (4, 4)

Fcritical=

[tex]F_{0.1},(4,4)\\\\[/tex]

Fcritical = 4.11

Critical value = 4.11

Here,

F test Statistic < critical value

so we fail to reject null hypothesis H₀

Conclusion

There is insufficient evidence to conclude the standard deviations are different.

we may assume they are equal.

April and Blake went running. Blake

ran 4 miles farther than April. Added

together, they ran a total of 16 miles.

How far did April run?

X = April's distance

4 + x = Blake's distance

Answers

Answer:

6 miles

Step-by-step explanation:

From the information given you can write the following equation:

x+y= 16 (1), where

x= April's distance

y= Blake's distance

You also have that Blake ran 4 miles farther than April which means that y= 4+x and you can replace this in the first equation and isolate x:

x+(4+x)= 16

x+4+x=16

2x=16-4

x=12/2

x= 6

According to this, the answer is that April ran 6 miles.

g(x) = 3x + 3, find g(6).

Answers

Answer:

Step-by-step explanation:

g(6) = 3(6) + 3

      = 18+3

      = 21

4x – 8 + 6x – 12 = 10

Answers

Step-by-step explanation:

4x+6x-8-12=10

10x-20=10

10x=10+20

10x=30

x=3

Answer:

x=3

Step-by-step explanation:

to find X first find the like terms

like terms: 4x and 6x

like terms: -12 and -8

combine the like the like terms

4x+6x=10x

-12-8=-20

10x-20=10

add 20 on both sides

10x-20+20=10+20

10x=30

divide both sides by 10

10x/10=30/10

x=3

ANSWER CHECK

substitute the variable

4(3) – 8 + 6(3) – 12 = 10

12-8+18-12

4+18-12

22-12 = 10

10=10

If the quarter circle intersects the x-axis at the coordinate (- 3, 0) and is rotated around the y-axis what is the resulting 3 - D figure and determine its volume to the nearest cubic unit.

Answers

Answer:

Volume of the hemisphere will be 57 cubic units.

Step-by-step explanation:

A quarter circle which intersects the x-axis at (-3, 0) when rotated around the y-axis, 3-D figure formed will be a hemisphere.

As shown in the figure attached,

Radius of the hemisphere formed = 3 units

Volume of the hemisphere = [tex]\frac{1}{2}(\frac{4}{3})\pi (r)^{3}[/tex]

                                             = [tex](\frac{2}{3})\pi (r)^{3}[/tex]

                                             = [tex]\frac{2}{3}\pi (3)^{3}[/tex]

                                             = 18π

                                             = 56.55 cubic units

                                             ≈ 57 cubic units

Therefore, volume of the hemisphere will be 57 cubic units

A math teacher tells her students that eating a healthy breakfast on a test day will help their brain function and perform well on their test. During finals week, she randomly samples 46 students and asks them at the door what they ate for breakfast. She categorizes 26 students into Group 1 as those who ate a healthy breakfast that morning and 20 students into Group 2 as those who did not. After grading the final, she finds that 50% of the students in Group 1 earned an 80% or higher on the test, and 40% of the students in Group 2 earned an 80% or higher. Can it be concluded that eating a healthy breakfast improves test scores? Use a 0.05 level of significance.

Answers

Answer:

Step-by-step explanation:

Hello!

To test the claim that eating a healthy breakfast improves the performance of students on their test a math teacher randomly asked 46 students what did they have for breakfast before they took the final exam and classified them as:

Group 1: Ate healthy breakfast

X₁: Number of students that ate a healthy breakfast before the exam and earned 80% or higher.

n₁= 26

Group 2: Did not eat healthy breakfast

X₂: Number of students that did not eat a healthy breakfast before the exam and earned 80% or higher.

n₂= 20

After the test she counted the number of students that got 80% or more in the test for each group obtaining the following sample proportions:

p'₁= 0.50

p'₂= 0.40

The parameters of study are the population proportions, if the claim is true then p₁ > p₂

And you can determine the hypotheses as

H₀: p₁ ≤ p₂

H₁: p₁ > p₂

α: 0.05

[tex]Z= \frac{(p'_1-p'_2)-(p_1-p_2)}{\sqrt{p'(1-p')[\frac{1}{n_1} +\frac{1}{n_2}] } } }[/tex]≈N(0;1)

pooled sample proportion: [tex]p'= \frac{x_1+x_2}{n_1+n_2} =\frac{13+8}{46} = 0.46[/tex]

[tex]Z_{H_0}= \frac{(0.5-0.4)-0}{\sqrt{0.46(1-0.46)[\frac{1}{26} +\frac{1}{20}] } } }= 0.67[/tex]

p-value: 0.2514

The decision rule is:

If p-value ≤ α, reject the null hypothesis.

If p-value > α, do not reject the null hypothesis.

The p-value: 0.2514 is greater than the significance level 0.05, the test is not significant.

At a 5% significance level you can conclude that the population proportion of math students that obtained at least 80% in the test and had a healthy breakfast is equal or less than the population proportion of math students that obtained at least 80% in the test and didn't have a healthy breakfast.

So having a healthy breakfast doesn't seem to improve the grades of students.

I hope this helps!

A store finds that its sales revenue changes at a rate given by S'(t) = −30t2 + 420t dollars per day where t is the number of days after an advertising campaign ends and 0 ≤ t ≤ 30. (a) Find the total sales for the first week after the campaign ends (t = 0 to t = 7). $ (b) Find the total sales for the second week after the campaign ends (t = 7 to t = 14). $ g

Answers

Answer:

Step-by-step explanation:

Give the rate of change of sales revenue of a store modeled by the equation [tex]S'(t)= -30t^{2} + 420t[/tex]. The Total sales revenue function S(t) can be gotten by integrating the function given as shown;

[tex]\int\limits {S'(t)} \, dt = \int\limits ({-30t^{2}+420t }) \, dt \\S(t) = \frac{-30t^{3} }{3}+\frac{420t^{2} }{2}\\ S(t)= -10t^{3} +210t^{2} \\[/tex]

a) The total sales for the first week after the campaign ends (t = 0 to t = 7) is expressed as shown;

[tex]Given\ S(t) = -10t^{3} + 210t^{2}[/tex]

[tex]S(0) = -10(0)^{3} + 210(0)^{2}\\S(0) = 0\\S(7) = -10(7)^{3} + 210(7)^{2}\\S(7) = -3430+10,290\\S(7) = 6,860[/tex]

Total sales = S(7) - S(0)

= 6,860 - 0

Total sales for the first week = $6,860

b) The total sales for the secondweek after the campaign ends (t = 7 to t = 14) is expressed as shown;

Total sales for the second week = S(14)-S(7)

Given S(7) = 6,860

To get S(14);

[tex]S(14) = -10(14)^{3} + 210(14)^{2}\\S(14) = -27,440+41,160\\S(14) = 13,720[/tex]

The total sales for the second week after campaign ends = 13,720 - 6,860

= $6,860

Principal = $5,400, rate = 18%, time = 2 years. What is the simple interest?

Answers

Answer:

$1,944.00

Step-by-step explanation:

Interest= Principal x Rate x Time (years)

Rate: 18%= 0.18

Interest= 5,400 x 0.18 x 2= $1,944

The quantities xxx and yyy are proportional. xxx yyy 777 353535 121212 606060 202020 100100100 Find the constant of proportionality (r)(r)left parenthesis, r, right parenthesis in the equation y=rxy=rxy, equals, r, x.

Answers

Answer: The constant of proportionality is r = 5.

Step-by-step explanation:

O, we know that x and y are proportional, this means that:

y = r*x

where r is the constant of proportionality.

we also have the table

x    y

7    35

12   60

20   100

Now, we can replace those values in our equation and get, for the first pair:

35 = r*7

r = 35/7 = 5

for the second pair:

60 = r*12

60/12 = 5 = r

So we can conclude that the constant of proportionality is 5.

Answer:

5

Step-by-step explanation:

It was right for me on khan

How do you factor the trinomial 3x^2+18x-21?

Answers

Answer:

(3)(x+7)(x-1)

Step-by-step explanation:

3x^2+18x-21

Let's start by taking 3 out of the equation.

3(x^2+6x-7)

Now, when we factor, we need to find two numbers that add up to 6 and multiply to -7.

The numbers would be 7 and -1.

So the factored form of this would be:

(3)(x+7)(x-1)

Football and Cognitive Percentile A recent study1 examined several variables on collegiate football players, including the variable Years, which is number of years playing football, and the variable Percentile, which gives percentile on a cognitive reaction test. The regression line for predicting Percentile from Years is: . 1Singh R, et al., "Relationship of Collegiate Football Experience and Concussion with Hippocampal Volume and Cognitive Outcomes", JAMA, 311(18), 2014. Data values are estimated from information in the paper. Predict the cognitive percentile for someone who has played football for 11 years and for someone who has played football for 17 years. Enter the exact answers.

Answers

Complete Question:

Football and Cognitive Percentile A recent study1 examined several variables on collegiate football players, including the variable Years, which is number of years playing football, and the variable Percentile, which gives percentile on a cognitive reaction test. The regression line for predicting Percentile from Years is:

Percentile = 102 - 3.34(years)

1Singh R, et al., "Relationship of Collegiate Football Experience and Concussion with Hippocampal Volume and Cognitive Outcomes", JAMA, 311(18), 2014. Data values are estimated from information in the paper. Predict the cognitive percentile for someone who has played football for 11 years and for someone who has played football for 17 years. Enter the exact answers.

Answer:

cognitive percentile for someone who has played football for 11 years = 65.26

cognitive percentile for someone who has played football for 17 years = 45.22

Step-by-step explanation:

This is a very straight forward question. The regression line for predicting percentile from the number of years has been explicitly given in the question as:

Percentile = 102 - 3.34(years)

Therefore,

the cognitive percentile for someone who has played football for 11 years will be calculated as:

Percentile = 102 - 3.34(11)

Percentile = 102 - 36.74

Percentile = 65.26

the cognitive percentile for someone who has played football for 17 years will be calculated as:

Percentile = 102 - 3.34(17)

Percentile = 102 - 56.78

Percentile = 45.22

A crop scientist is conducting research with a drought resistant corn hybrid. She is interested in determining if increasing the spacing between these plants will increase yield. She prepares 30 single acre plots and randomly assigns 15 to have normal spacing while the other 15 are planted with an expanded spacing. The resulting average yield for each group of 15 plots was recorded.

Select all that apply.

Select one or more:
a. The explanatory variable is whether the corn plants had normal spacing or expanded spacing.
b. The response variable is the yield of the crops.
c. The explanatory variable is the yield of the crops.
d. The response variable is whether the corn plants had normal spacing or expanded spacing.
e. This study is best described as an experiment.
f. This is best described as an observational study.

Answers

Answer:

A , B and E.

Step-by-step explanation:

the scientist can control and deal with the measure of manure that is given to a solitary corn plants. thus A is correct.

The reaction variable is the yield recorded for each plot due to the fact that the yield recorded in each plot is needed to check  whether the compost is given or not. choice B is also correct

it's considered an experiment because the specialist is controlling the autonomous variable. then E is a right choice.

The explanatory variable is whether the corn plants had normal spacing or expanded spacing.

The response variable is the yield of the crops.

This study is best described as an experiment.

verify 10÷(6+4)≠(10÷6)+(10÷4)​

Answers

Please see attached picture for full solution

Hope it helps

Good luck on your assignment

The range of the data: 7, 10, 30, 16, 8, 5, 3, 18, 35, and 1 tell the answer only

Answers

It is 32 because highest number subtracted by lowest

Range of data = [tex]\boxed{\sf{\red{Highest-lowest}}}\\[/tex]

Data = 1, 3 , 5 , 7 , 8 , 10 , 16 ,18 , 30, 35

Range = 35 - 1

Range of data is 34.

Determine the measure of angle P if the measure of arc BD is 154 degrees and secant AD is a diameter of Circle C.

Answers

Complete Question

The complete question is shown on the first uploaded image

Answer:

The angle P is  [tex]P = 26^o[/tex]

Step-by-step explanation:

From the question we are told that

    The angle BD is  [tex]BD = 154^o[/tex]

Now looking at the diagram we can deduce that angle [tex]B \r CD = 180 ^o[/tex]

Now looking at line AD we see that it is tangent to the circle this implies that line CD is perpendicular to line AD

   So  we can also deduce that

            [tex]B \r C A + D \r C A = 180[/tex]

=>       [tex]D \r C A = 180 - 154[/tex]

=>       [tex]D \r C A = 26^o[/tex]

 Now total angle in a triangle is 180 so

        [tex]C\r DA + D\r A C + A \r C D = 180^o[/tex]

Now  [tex]D \r A C = 90^o[/tex]

So  

          [tex]D \r AC = 180 - (90 + 26)[/tex]

=>      [tex]P = D \r AC = 26^o[/tex]

find the distance between (8, -4) and (2, 15). round to the nearest tenth

Answers

Answer:

19.9

Step-by-step explanation:

d = sqrt(6^2+19^2) = sqrt( 397) =. 19.9

The answer is 19.9
Kanan

A vegetable garden and surrounding path are shaped like a square that together are 10ft wide. The path is 3ft wide. Find the total area of the vegetable garden and path.

Answers

Answer:

256

Step-by-step explanation:

since the the path surounds both sides of the garden you have to add 2 x instead of just x

let me show you what i mean. 10=garden width and 3=path width=x

since it is a square, we can calculate the area by taking one side and squaring it so you get (10+2x)^2 which is 16^2 since x is 3, the width of the garden

to do simaler problems just use thei formula (garden length+2path length)^2 or (garden length+2path length)times(garden length+2path length)

I need Help The question is Really complicated

Answers

Answer:

Graph A

Step-by-step explanation:

A linear association means that the dots form a line

Answer:

The answer is A

Step-by-step explanation:

A linear association is when the dots on the graph create a straight line. A creates a straight line therefore it is a linear association.

a 129$ golf club is on sale for 30% off. if sales tax is 6.25% what will be the final cost of the golf club with the discount and sales tax?

Answers

Answer:

approximately $95.94375

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