1. Survey of Music Preferences of College Students
Data File:MusicSurvey.JMP
Keywords: Statistical Inference for Population Means

Suppose you are working for a company in the music business. They make stereos, musical instruments, produce CD's, etc. Their business is in a slump. So they decided to do a survey of college students on a variety of issues, presumably to develop an effective ad campaign and perhaps restructure their operation. Basically, they wanted to know about college students' interests and practices vis-à-vis music.

Their survey was administered to a random sample of students taking a course in elementary statistics at WinonaState. Their resources were a bit limited so they decided to save money by picking a "typical" state university to do the survey. They asked a stat instructor if he would have students in his Stat 110 class fill out the survey. The instructor said he had already planned on having students fill out a survey for use in class projects, so he would just add in the items the company was interested in.

The president of the company hired the members of your group to look at the data, prepare a report to her, and do whatever statistical analyses appropriate to support your conclusions and recommendations. They hired you after the survey was completed, so you had no opportunity to suggest changes in the survey and/or how and to whom it would be administered.

The 20-item survey is give below:
Q1. What is your gender? Male ___ Female ___
Q2. What is your race? Caucasian ___ Non-Caucasian ___
Q3. Which kind of growth is most important in college? Intellectual ___ Social ___
Q4. What type of TV show do you prefer to watch? Comedy __ Drama ___ Mini-Series ___ Other ___
Q5. What is your favorite kind of music? Alternative ___ Classic Rock ___ Rap ___ Top 40 ___ Other ___
Q6. What is your least favorite kind of music? Heavy metal ___ Rap ___ Country ___ Other ___
Q7. Does MTV show favoritism in type of music played? No ___ Yes ___ Don't know __
Q8. Do you belong to a music club? No ___ Yes ___
Q9. Do you watch music videos? No ___ Yes ___
Q10. Which do you prefer? MTV ___ VH1 ___ No preference ____
Q11. How many music CDs do you buy each year? Number of CDs ____
Q12. On average, how much money do you spend per month on Cds? Dollars _____
Q13. How much are you willing to spend on a stereo system? Dollars _____
Q14. Do you play at least one musical instrument? No ___ Yes ___
Q15. How many "albums" have you bought in the last year? Number of Albums ____
Q16. About how many CDs or cassettes do you own? Number of CDs or Cassettes ____
Q17. If you were stranded on a deserted island, which would you prefer to have?
Telephone ___ TV ___ CD player/stereo ___
Q18. Do you prefer to study with music or without music? Without music ___ With music ___
Q19. Do you feel that your interests in music have broadened since coming to college? No ___ Yes ___
Q20. Do you have a significant other? No ___ Yes ___

a) Depending on where you shop the price of a typical CD is about $13.99. Is there evidence that the mean amount spent on music per month of college students exceeds the price of a typical CD? (3 pts.)

b) Provide a range of values that are likely to cover the mean amount college students would be willing to spend on a stereo system. Give the correct interpretation of this interval. Do you have any concerns regarding the appropriateness of your estimate?
(3 pts.)

c) What might conjecture that college students who are members of music clubs spend more money on CDs per month than college students who do not belong to music clubs. Is this conjecture supported by these data? Perform the appropriate test and discuss the results. (4 pts.)

2. Risk Factors for Having a Child with Low Birth Weight
Data File:Lowbirth.JMP

The purpose of this study was to identify potential risk factors for low birth weight. A random sample of new mothers was taken and the birth weight was recorded. Also the following categorical variables were measured for mother:

  • Whether or not the woman had a previous history of premature labor (Prev?)
  • Whether or not she was hypertensive during pregnancy (Hyper?)
  • Whether or not she smoked during pregnancy (Smoke?)
  • Whether or not she had uterine irritability during pregnancy (Uterine)
  • Whether the mother was a minority (Minority)

Use comparative methods to compare the mean birth weights across the levels of these five factors.Make a table of the following form:

Potential
Risk Factor / Sample Mean
(Risk Factor Present) / Sample Mean
(Risk Factor Absent) / p-value / Confidence Interval for

a) For which risk factors have significant differences between the mean birth weights?

b) Which factors have the largest birth weight differences?

Use both hypothesis tests and confidence intervals to justify your conclusions. Summarize your findings in a clearly written paragraph. (20 pts.)

(NOTE: 1 lb. = 454 grams, so if you divide the birth weight column by 454 you will have birth weight in pounds.)