/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Q. 93 Have a ball! Can students throw ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

Have a ball! Can students throw a baseball farther than a softball? To find out, researchers conducted a study involving 24randomly selected students from a large high school. After warming up, each student threw a baseball as far as he or she could and threw a softball as far as he she could, in a random order. The distance in yards for each throw was recorded. Here are the data, along with the difference (Baseball – Softball) in distance thrown, for each student:

a. Explain why these are paired data.

b. A boxplot of the differences is shown. Explain how the graph gives some evidence that students like these can throw a baseball farther than a softball.

c. State appropriate hypotheses for performing a test about the true mean difference. Be sure to define any parameter(s) you use.

d. Explain why the Normal/Large Sample condition is not met in this case. The mean difference (Baseball−Softball) in distance thrown for these 24students is xdiff = 6.54yards. Is this a surprisingly large result if the null hypothesis is true? To find out, we can perform a simulation assuming that students have the same ability to throw a baseball and a softball. For each student, write the two distances thrown on different note cards. Shuffle the two cards and designate one distance to baseball and one distance to softball. Then subtract the two distances (Baseball−Softball) . Do this for all the students and find the simulated mean difference. Repeat many times. Here are the results of 100trials of this simulation

e. Use the results of the simulation to estimate the P-value. What conclusion would you draw ?

Short Answer

Expert verified

Part(a) These are to utilise paired t methods because the two samples contain the identical participants.

Part(b) The boxplot is to the right of zero, indicating that the majority of the distances are positive, and so the distance in baseball is higher than in softball.

Part(c) The appropriate hypotheses is :

H0:μD=0Ha:μD>0

Part(d) Because the distribution of the differences is considerably skewed to the right due to the outlier to the right in the boxplot, the distribution is not approximately normal.

Part(e) There is convincing evidence that student like these can throw baseball farther than soft ball.

Step by step solution

01

Part(a) Step 1 : Given information

We need to explain the paired data.

02

Part(a) Step 2 : Simplify

If the two samples contain the same individuals or if the subjects in one sample are connected to the subjects in the other sample, we must employ paired t methods.
If the subjects in the two samples are fully unrelated, we must employ two sample t methods.
In this scenario, we have the baseball distance thrown and the softball distance thrown for 24students each.
As a result, the first sample is the baseball distance thrown, whereas the second sample is the softball distance thrown.
We should utilise paired t methods because the two samples contain the identical participants.

03

Part(b) Step 1 : Given information

We need to explain given boxplot.

04

Part(b) Step 2 : Simplify

Students like them, it is believed, can throw a baseball farther than a softball.
The data in the boxplot reflects the difference in distance between the 24students' baseball and softball distances.
We can see that the majority of the boxplot is to the right of zero, indicating that the majority of the distances are positive, and so the distance in baseball is higher than in softball.
This supports the allegation, thus there is some evidence to back it up.

05

Part(c) Step 1 : Given information

We need to state hypotheses for performing a test about the true mean difference.

06

Part(c) Step 2 : Simplify

As a result, the claim that the mean difference is positive is correct.
Now we must determine the most relevant hypotheses for a significance test.
As a result, either the null hypothesis or the alternative hypothesis is the claim.
According to the null hypothesis, the population proportions are equal.
If the claim is the null hypothesis, the alternative hypothesis is the polar opposite of the null hypothesis.
As a result, the following assumptions are appropriate:

H0:μD=0Ha:μD>0
Here, μDis the mean difference in thrown distance between the baseball and the softball.

07

Part(d) Step 1 : Given information

We need to explain why Normal/Large Sample condition is not met in this case.

08

Part(d) Step 2 : Simplify

The normal or big condition necessitates either a large sample or a distribution of differences that is roughly normal.
The sample isn't big enough because the sample size is only 24, which isn't even close to 30.
Because the distribution of the differences is considerably skewed to the right due to the outlier to the right in the boxplot, the distribution is not approximately normal.
This indicates that the condition has not been met.

09

Part(e) Step 1 : Given information

We need to estimate the P-value to draw conclusion.

10

Part(e) Step 2 : Simplify

As given in the question , n=24

Mean : x=∑i=1nxin=8+32+9+12+14+12+5+0+12+5+7+2+18-3+9+6+2+1+3+1+3+1+3-524=15724=6.5417

P-value is probability of obtaining sample results.

P-value =010=0

As P-value is less than or equal to significance level then null hypothesis is rejected.

P<0.05→RejectH0

Therefore, At the α=0.05 level , students like these can throw baseball faster than softball.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Broken crackers We don’t like to find broken crackers when we open the package. How can makers reduce breaking? One idea is to microwave the crackers for 30seconds right after baking them. Randomly assign 65newly baked crackers to the microwave and another 65to a control group that is not microwaved. After 1day, none of the microwave group were broken and 16of the control group were broken. Let p1be the true proportions of crackers like these that would break if baked in the microwave and p2be the true proportions of crackers like these that would break if not microwaved. Check if the conditions for calculating a confidence interval forp1-p2met.

Let pM,pFbe the proportions of all college males and

females who worked last summer. The hypotheses to be tested are

a. H0:pM-pF=0versesHa:pM-pF≠0

b. H0:pM-pF=0versesHa:pM-pF>0

c. H0:pM-pF=0versesHa:pM-pF<0

d. H0:pM-pF>0versesHa:pM-pF=0

e.H0:pM-pF≠0versesHa:pM-pF=0

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 of 40high 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: μsuburban=μcity versus a two-sided alternativ

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

a. fail to reject H0because0.048<α=0.05. 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 H0because 0.048<α=0.05. There is not 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 H0because0.048<α=0.05. 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 H0because 0.048<α=0.05. There is not convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

e. reject H0because 0.048<α=0.05 . There is convincing evidence of a difference in the average time spent on extracurricular activities by students in the suburban and city school districts.

Does drying barley seeds in a kiln increase the yield of barley? A famous

experiment by William S. Gosset (who discovered the t distributions) investigated this

question. Eleven pairs of adjacent plots were marked out in a large field. For each pair,

regular barley seeds were planted in one plot and kiln-dried seeds were planted in the

other. A coin flip was used to determine which plot in each pair got the regular barley seed

and which got the kiln-dried seed. The following table displays the data on barley yield

(pound per acre) for each plot.

Do these data provide convincing evidence at the α=0.05 level

that drying barley seeds in a kiln increases the yield of barley, on average?

Young adults living at home A surprising number of young adults (ages 19

to 25) still live in their parents’ homes. The National Institutes of Health surveyed

independent random samples of 2253men and 2629women in this age group. The survey found that 986 of the men and 923 of the women lived with their parents.

a. Construct and interpret a 99%confidence interval for the difference in the true

proportions of men and women aged 19-25who live in their parents’ homes.

b. Does your interval from part (a) give convincing evidence of a difference between the population proportions? Justify your answer.

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.