2. Move to the Exchange Rates sheet in this file. Column A (cells A2:A194) contains the population of exchange rates. Create a random sample of exchange rates in Column A of the Experiment1 Worksheet (starting in A4), use the sequence Tools Menu--Data Analysis--Sampling. In the sampling window designate the population location under the input range as A2:A194 (do not check labels). Record the sample size, n, number of samples under Random. Use n = 40. Finally under output range designate Experiment1!A4 as the destination. Click OK and move to the Experiment1 worksheet.
3. The random sample is in A4:A43. I programmed Excel to compute the confidence interval and relevant statistics after you designate the confidence level in D10. Start with an 80% confidence interval by typing 80 in D10. Record the limits of the confidence interval in the following table. Repeat this experiment (Steps 2 & 3) five times.
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Confidence Level Interpretation Experiment |
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Trials |
Lower Limit |
Upper Limit |
U = Contains m |
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5. Transfer to the Experiment2 worksheet. Only substitute values in the n, S, and Confidence Level columns (the other columns contain preprogrammed formulas).
a. Record the same S value and the same Confidence Level value for all 13 trials. Then type in 13 different n values in ascending order. What happens to the width of the confidence intervals as n increases? Explain the result intuitively. Show what happens in the confidence interval formula when n increases.
b. Repeat Part a with constant n and S for all trials, while Confidence Level increases.
c. Repeat Part a with constant n and Confidence Level for all trials, while S increases.
6. Repeat Experiment 1 (Steps 2-4) with n=10 and
the Experiment3 worksheet. Is the population normal?