1. Find a 90% confidence interval for the population mean if the sample mean is 1462 with a standard deviation of 42 for a sample of 20.
2. Find the minimum sample size to find the 90% interval estimate for a population proportion if you want to be accurate to 4%.
3. The mean time before a certain headache remedy starts to work is 12 minutes with a standard deviation of 3.  A new coating is used to help swallow the pill.  A sample of 38 people using the pills with the new coating showed the mean time before it started to work was 14 minutes.  Is there a difference with the new coating?
   Test at the  .01 level.  State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision, and summarize the results.
4. A copy machine is advertised as doing 25,000 copies before requiring service.  A consumer group wants to check this claim.  If 12 customers had a mean of 24,800 copies with a standard deviation of 180, test at the  .01 level.
   State the hypotheses and identify the claim, find the critical value(s), compute the test value, and make the decision, summarize the results.
5. A manufacturer wants to know if the variance of their product is 84 if a sample of 28 had a variance of 79.      Test the claim at the .05 level.
   State the hypotheses and identify the claim, find the critical value(s), compute the test value, and make the decision, summarize the results.
6. A researcher estimates that high school girls miss more days of school than high school boys. A sample of 16 girls showed that they missed an average of   3.9 days of school per school year; a sample of 22 boys showed that they missed an average of   3.6 days of school per year.  The standard deviations are   0.6 and   0.8 respectively.  At a significance level of   0.01, is there enough evidence to support the researcher's claim.
   State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision, summarize the results.
7. IQ tests were administered to 12 subjects at 8 a.m.  Two months later, the same test was administered to the same subjects at 4 p.m.  Test at the .01 level to see if there is a difference in the performances.
   State the hypotheses and identify the claim, find the critical value(s), compute the test value, and make the decision, summarize the results.
   
8. In a recent survey of 50 apartment residents, 32 had microwave ovens. In a survey of 60 homeowners, 24 had microwave ovens.  At a significance level of  0.05, test the claim that the proportions are equal.  Find the 95% confidence interval for the difference of the two proportions.
   State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision and summarize the results.
9. Use the following data to:

1. draw a scatter plot
2. find the coefficient of correlation and test the significance at the .05 level
3. find the coefficients of determination and non-determination
4. find the regression line
5. predict y' for x=5
6. find the standard error of estimate

10.  A company had 36 absences on Monday, 26 on Tuesday, 10 on Wednesday, 20 on Thursday, and 28 on Friday. At the  .05 level, is there a difference in the number of absence per day?

State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision, summarize the results.

11.  If the null hypothesis is rejected use the Scheffe' test when the sample sizes are unequal to test the differences between the means, and use the Tukey test when the sample sizes are equal.       Test at the   .05 significance level.

State the hypotheses and identify the claim, find the critical value(s), compute the test value, make the decision, summarize the results, and explain where the differences in means are.

The head of the English dept. wants to determine if the average number of students taking an English course differs depending upon the time of day that the court is being offered.

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Solution: The downloadable solution consists of 14 pages, 1717 words and 4 charts.
Deliverable: Word Document