1) If 100 randomly selected runners from a race can complete a mile run with an average time of 9 minutes with a standard deviation of 30 seconds, find a 95% confidence interval for the average time on all the runners in the race. 2) Based on a sample of 100 participants, a 95% confidence interval for the average SAT score for individuals who took a prep course is 11.4 points plus or minus .51. Interpret this confidence interval. 3) Suppose survey results say that 69% of adult females from a sample taken of shoppers use a credit card when making purchases. The margin of error for the survey that produced these results was +/- three percent. Interpret these values. 4) A sample size of 100 produced the sample mean of 16 with a standard deviation of 3. Compute a 95% confidence interval for the population mean. 5) A sample of 30 individuals has a mean score on a test of 58 with a standard deviation of 3.2. Compute a 99% confidence interval based on this sample data. 6) A sample of data from car lot had the following consumption of gasoline in gallons. 32, 16, 25, 22, 27, 19, 20. Calculate a 90% confidence interval for the mean daily use of gasoline. 7) Suppose you have selected a sample of data with values: 4,6,3,5,9,3. Construct a 90% confidence interval for the population mean. 8) A random sample of 90 observations produced a mean of 25.9 and a standard deviation of 2.7. Find a 95% confidence interval for the population mean. 9) A random sample of 90 observations produced a mean of 25.9 and a standard deviation of 2.7. Find a 90% confidence interval for the population mean. 10) A random sample of 90 observations produced a mean of 25.9 and a standard deviation of 2.7. Find a 99% confidence interval for the population mean. How does this interval differ from the two you calculated in problems 8 and 9? 11) Did your research article have enough data to assume it was normally distributed? Did it use an appropriate confidence interval? If the sample size was too small, did they mention the use of a ttest?