1. The following sample data are from a normal population: 10, 8, 12, 15, 13, 11, 6, 5. a. What is the point estimate of the population mean?
b. What is the point estimate of the population standard deviation?
c. With 95% confidence, what is the margin of error for the estimation of the population mean?
d. What is the 95% confidence interval for the population mean
2. In a survey, the planning value for the population proportion is p* = .35 . How large a sample should be taken to provide a 95% confidence interval with a margin of error of .05?
3. At 95% confidence, how large a sample should be taken to obtain a margin of error of .03 for the estimation of a population proportion? Assume that past data are not available for developing a planning value for p* .
4. Internet users were recently asked online to rate their satisfaction with the web browser they use most frequently. Of 102,519 respondents, 65,120 indicated they were very satisfied with the web browser they use most frequently.
a. What is the sample proportion of Internet users who are very satisfied with the web browser they use most frequently?
b. Using 95% confidence, what is the margin of error?
c.Using the results from parts
(a) and
(b), develop the 95% confidence interval estimate of the proportion of Internet users who are very satisfied with the web browser they use most frequently.
