Winter Olympics 2006 speed skating. The top 25 women's 500-m speed skating times are listed in the table:
a) The mean finishing time was 78.21 seconds, with a standard deviation of 1.03 seconds. If the Normal model is appropriate, what percent of the times should be within 0.5 second of 78.21?
b) What percent of the times actually fall within this interval?
c) Explain the discrepancy between a and b.