A researcher wished to compare the average amount of time spent in extracurricular activities by high school students in a suburban school district with that in a school district of a large city. The researcher obtained an SRS of 60high school students in a large suburban school district and found the mean time spent in extracurricular activities per week to be 6hours with a standard deviation of 3hours. The researcher also obtained an independent SRS of40high school students in a large city school district and found the mean time spent in extracurricular activities per week to be 5hours with a standard deviation of 2hours. Suppose that the researcher decides to carry out a significance test of H0:μmibratum=μcillyversus a two-sided alternative

The P-value for the test is 0.048. A correct conclusion is to

(a) fail to reject H0at the role="math" localid="1650370033639" α=0.05level. There is convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

(b) fail to reject H0at the role="math" localid="1650370045107" α=0.05level. There is no convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

(c) fail to reject H0at the role="math" localid="1650370055451" α=0.05level. There is convincing evidence that the average time spent on extracurricular activities by students in the suburban and city school districts is the same.

(d) reject H0at the role="math" localid="1650370062817" α=0.05level. There is no convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

(e) reject H0 at the role="math" localid="1650370172076" σ=0.05 level. There is convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

Short Answer

Expert verified

The correct conclusion is option (e) reject H0at theα=0.05 level. There is convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

Step by step solution

01

Given information

The first number of high school is60

Mean is6

Standard deviation is3

The second number of high school is40

Mean is5

Standard deviation is2.

02

Explanation

The given value is

P=0.048

The null hypothesis is rejected if the P-value is less than or equal to the significance level:

P<0.05RejectH0

There is sufficient evidence of a difference between the population means reject H0 at the α=0.05level.

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Most popular questions from this chapter

42. Long words Mary was interested in comparing the mean word length in articles from a medical journal and an airline’s in-flight magazine. She counted the number of letters in the first 200 words of an article in
the medical journal and in the first 100 words of an article in the airline magazine. Mary then used Minitab statistical software to produce the histograms shown.

A beef rancher randomly sampled 42cattle from her large herd to obtain a 95%confidence interval to estimate the mean weight of the cows in the herd. The interval obtained was 1010,1321. If the rancher had used a 98%confidence interval instead, the interval would have been

(a) wider and would have less precision than the original estimate.

(b) wider and would have more precision than the original estimate.

(c) wider and would have the same precision as the original estimate.

(d) narrower and would have less precision than the original estimate.

(e) narrower and would have more precision than the original estimate.

The following dot plots show the average high temperatures (in degrees Fahrenheit) for a sample of tourist cities from around the world. Both the January and July average high temperatures are shown. What is one statement that can be made with certainty from an analysis of the graphical display?

(a) Every city has a larger average high temperature in July than in January.

(b) The distribution of temperatures in July is skewed right, while the distribution of temperatures in January is skewed left.

(c) The median average high temperature for January is higher than the median average high temperature for July.

(d) There appear to be outliers in the average high temperatures for January and July.

(e) There is more variability in average high temperatures in January than in July.

“Would you marry a person from a lower social class than your own?” Researchers asked this question of a random sample of 385black, never married students at two historically black colleges in the South. Of the 149men in the sample, 91said “Yes.” Among the 236women, 117said “Yes.”14Is there reason to think that different proportions of men and women in this student population would be willing to marry beneath their class?

Holly carried out the significance test shown below to answer this question. Unfortunately, she made some mistakes along the way. Identify as many mistakes as you can, and tell how to correct each one.

State: I want to perform a test of

H0:p1=p2

Ha:p1p2

at the 95%confidence level.

Plan: If conditions are met, I’ll do a one-sample ztest for comparing two proportions.

  • Random The data came from a random sample of 385 black, never-married students.
  • Normal One student’s answer to the question should have no relationship to another student’s answer.
  • Independent The counts of successes and failures in the two groups91,58,117, and 119are all at least 10

Do: From the data, p^1=91149=0.61and p^2=117236=0.46.

Test statistic

z=(0.61-0.46)-00.61(0.39)149+0.46(0.54)236=2.91

p=value From Table A, role="math" localid="1650292307192" P(z2.91)1-0.39820.0018.

Conclude: The p-value, 0.0018, is less than 0.05, so I’ll reject the null hypothesis. This proves that a higher proportion of men than women are willing to marry someone from a social class lower than their own.

Refer to Exercise 15.

(a) Carry out a significance test at the α=0.05level.

(b) Construct and interpret a 95%confidence interval for the difference between the population proportions. Explain how the confidence interval is consistent with the results of the test in part (a).

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