Learning Materials
Features
Discover
Chapter 10: Q 31. (page 643)
Let be the proportions of all college males and
females who worked last summer. The hypotheses to be tested are
a.
b.
c.
d.
e.
Option (a) is correct.
Over 30 million students worldwide already upgrade their learning with 91影视!
All the tools & learning materials you need for study success - in one app.
Get started for free
On your mark In track, sprinters typically use starting blocks because they think it will help them run a faster race. To test this belief, an experiment was designed where each sprinter on a track team ran a -meter dash two times, once using starting blocks and once with a standing start. The order of the two different types of starts was determined at random for each sprinter. The times (in seconds) for 8 different sprinters are shown in the table.
a. Make a dotplot of the difference (Standing - Blocks) in -meter run time for each sprinter. What does the graph suggest about whether starting blocks are helpful?
b. Calculate the mean difference and the standard deviation of the differences. Explain why the mean difference gives some evidence that starting blocks are helpful.
c. Do the data provide convincing evidence that sprinters like these run a faster race when using starting blocks, on average?
d. Construct and interpret a confidence interval for the true mean difference. Explain how the confidence interval gives more information than the test in part (b).
The correlation between the heights of fathers and the heights of their grownup sons, both measured in inches, is. If fathers鈥� heights were measured in feet instead, the correlation between heights of fathers and heights of sons would be
a. much smaller than .
b. slightly smaller than .
c. unchanged; equal to .
d. slightly larger than .
e. much larger than .
Which of the following statements is false?
a. A measure of center alone does not completely summarize a distribution of quantitative data.
b. If the original measurements are in inches, converting them to centimeters will not change the mean or standard deviation.
c. One of the disadvantages of a histogram is that it doesn鈥檛 show each data value.
d. In a quantitative data set, adding a new data value equal to the mean will decrease the standard deviation.
e. If a distribution of quantitative data is strongly skewed, the median and interquartile range should be reported rather than the mean and standard deviation.
Steroids in high school A study by the National Athletic Trainers Association surveyed random samples of high school freshmen and 1366 high school seniors in Illinois. Results showed that of the freshmen and of the seniors had used anabolic steroids. Steroids, which are dangerous, are sometimes used in an attempt to improve athletic performance. Researchers want to know if there is a difference in the proportion of all Illinois high school freshmen and seniors who have used anabolic steroids.
a. State appropriate hypotheses for performing a significance test. Be sure to define the parameters of interest.
b. Check if the conditions for performing the test are met.
Music and memory Does listening to music while studying help or hinder students鈥� learning? Two statistics students designed an experiment to find out. They selected a random sample of students from their medium-sized high school to participate. Each subject was given minutes to memorize two different lists of words, once while listening to music and once in silence. The order of the two word lists was determined at random; so was the order of the treatments. The difference (Silence 鈭� Music) in the number of words recalled was recorded for each subject. The mean difference was and the standard deviation of the differences was .
a. If the result of this study is statistically significant, can you conclude that the difference in the ability to memorize words was caused by whether students were performing the task in silence or with music playing? Why or why not?
b. Do the data provide convincing evidence at the significance level that the number of words recalled in silence or when listening to music differs, on average, for students at this school?
c. Based on your conclusion in part (a), which type of error鈥攁 Type I error or a Type II error鈥攃ould you have made? Explain your answer.
What do you think about this solution?
We value your feedback to improve our textbook solutions.
Explanations 
Textbooks 
Flashcards 
91影视 AI 
Notes 
Study Plans 
Study Sets 
Find a degree 
Magazine