New York City 10-km Run.

9/3 = 3 mins

c. Construct graphs similar to those shown in Fig. 7.4 on page 311. So here's where the actual q starts. The graph they're referring to is the "not normal -> normal graph as it gets closer to n >= 30 or the Central Limit Theorem graph" and I know the sample size is not near 30 so it won't be a normal graph, unless of course it is so please help me. I have no clue how to divide the data. I know the mean is 61 minutes but that's it.

d. Obtain the percentage of all samples of four finishers that have mean finishing times within 5 minutes of the population mean finishing time of 61 minutes. Interpret your answer in terms of sampling error. I do not quite get this.

e. Repeat part d. for samples of size 9. Once i figure c and d then I can answer this solo probably.

Please help me with c and d.