Project 2 SU3
Math 131 Name:
Stat Project 2 Total Points: 14

INSTRUCTIONS: First, download the Excel Project 2 Data file from Canvas. The data is also
available in csv format in case you wish to use a software other than Excel. All solutions must
e typed into the Word document. Please submit the Word doc with your solutions, not the
Excel sheet that you use to do the computations. Use Excel to give you the solutions to
numbers 1 & 2, only. No handwritten solutions accepted.


DATA SET: A random sample of marathon training times, in minutes, for 30 female marathon
unners.
1. Excel: Find a point estimate for the mean marathon training time of female runners. (1pt)

2. Excel: Find the standard deviation of the sample of marathon training times of female
unners. (1pt)

3. Construct a 90% confidence interval for the population mean training time for women. Be
sure to show the margin of e
or computation. (2pts)

4. Interpret your results from #3 above. (2pts)

5. Construct a 95% confidence interval for the population mean training time for women. Be
sure to show the margin of e
or computation. (2pts)

6. Interpret your results from #5 above. (2pts)

7. Which confidence interval is wider and why? (2pts)

8. Determine the minimum sample size needed to create a 95% confidence interval such that
the sample mean is within 1.5 minutes of the population mean. Assume the population
standard deviation is the same as the sample standard deviation you found in #2. (2pts)