A sample of n+6 scores has a mean of x=20. If one person with a score of X =15 is removed from the sample,
2) A sample of \(n+6\) scores has a mean of \(\mathrm{x}=20\). If one person with a score of \(\mathrm{X}\) \(=15\) is removed from the sample, what will be the value for the new mean?
3) On an exam with \(\mu=82\), you obtain a score of \(X=87\).
- What would you prefer that the exam distribution had \(\sigma=2\) or \(\sigma=10\) ? Explain.
- If your score is \(X=75\), what would you prefer \(\sigma =10\) ? Explain.
4. Give a population of \(N=7\) and \(S S=217\),
- Find \(\sigma\)
- Find \(s\) for \(n=5\) and \(\mathrm{SS}=96\)
5. Give a mean of \(\bar{x}=20\) and \(s=2\), find the corresponding \(x\) values (to 2 decimal places) for the \(z\) -scores \(z=0.5, z=1.11\), and \(z=3.02\)
6. A trick coin has been weighted so that heads occur with a probability of \(p=\) \(3 / 5\) and \(\mathrm{p}\) (tails) \(=2 / 5\), If you toss this coin 35 times:
- How man heads would you expect to get an average?
- What is the probability of obtaining 25 heads or greater? (Consider using the normal approximation)
7. The population IQ scores forms a normal distribution with a mean of \(\mu = 100\) and a standard deviation of \(\sigma=15\). What is the probability of obtaining a sample man greater than \(\bar{x}=105\) for both \(n=9\) and \(n=36\) ?
8. A researcher is testing the hypothesis that Baby Wagner during play improves object recognition. A sample of \(n=36\) babies are tested, the overall number of correctly recognized objects score for the sample was \(\bar{x}=6\).
- If the population averages without Baby Wagner is \(\mu =5\) with \(\sigma=4\), determine if the Baby Wagner users have significantly higher scores. Use \(x=0.05\) for a one-tailed test.
- Determine the Cohen's \(d\) for the above, regardless of the test results.
Chapter 14 , #1
Use the gss.sav data file to answer the following questions:
- Perform the appropriate analyses to test whether the average number of hours of * daily television viewing (variable tvhours) is the same for men and women. Write a short summary of your results, including appropriate charts to illustrate your findings. Be sure to look at the distribution of hours of television viewed separately for men and women.
- Based on the results you observed, is it reasonable to conclude that in the population, men and women watch the same amount of television?
Chapter 14, #8
Use the salary.sav data file to answer the following questions:
8. Use the Select Cases facility to restrict the analysis to clerical workers only (variable jobcat equals 1).
- Test the assertion that male and female clerical workers have the same average starting salaries. Summarize your findings.
- You are \(95 \%\) confident that the true difference in average beginning salaries for male and female clerical workers is in what range?
- How often would you expect to see a difference at least as large in absolute value as the one you observed if, in fact, male and female clerical workers have the same beginning salaries?
- Evaluate how well your data meet the assumptions needed for a two-independent samples \(t\) test.
Chapter 14, #9
The bank claims that male clerical workers are paid more than female clerical workers because they have more formal education. Do the data support this assertion? Explain.
Chapter 13, #1
Use the gssft.sav data file to answer the following questions:
- Use the Compute facility (discussed in Appendix B) to create a new variable that is the difference between a husband's and wife's hours worked last week (variables husbhr and wifehr).
- Make a histogram of the difference. What should you look for in the histogram?
- Make a \(Q-Q\) plot of the differences. How does the distribution differ from the normal distribution?
- Do you think it's reasonable to believe that the distribution of mean differences is normal? Why? Perform a paired \(t\) test using the Paired-Samples T Test procedure. Write a brief summary of your results. Be sure to state your null and alternative hypotheses.
- Run a one-sample \(t\) test on the difference variable. Compare your results to those from the paired \(t\) test. In what ways are the two tests different?
Chapter 13, #4
Use the siqss.sav data file to answer the following questions:
4. Consider the difference between the number of e-mails a person sends in a day and the number of e-mails he or she receives.
- Compute a variable that is the difference between the number of e-mails a person sends (emsend) and the number of e-mails a person receives (emrec). Make a histogram. Describe the histogram. Are there outliers?
- Test the null hypothesis that the average number of e-mails sent is equal to the average number of e-mails received. What do you conclude?
- Use the Select Cases facility to remove outliers. Do your conclusions change?
Chapter 15, #1
Use the gss.sav data file to answer the following questions:
- In the General Social Survey people classified themselves as being very happy, pretty happy, or not too happy (variable happy). Consider the relationship between happiness and age.
- Compute basic descriptive statistics for each of the three happiness groups.
- Make boxplots of age for the three groups.
- Does the assumption of equal variances in the groups appear reasonable? The assumption of normality?
Chapter 15, #5
5. Fest whether Dole, Clinton, and Perot supporters (variable pres96) differ in average age and education. Summarize your findings.
Deliverable: Word Document
