Chapter 7.3, Problem 37E

A study of the ability of individuals to walk in a straight line (“Can We Really Walk Straight?” Amer. J. of Physical Anthro., 1992: 19–27) reported the accompanying data on cadence (strides per second) for a sample of n = 20 randomly selected healthy men.

A normal probability plot gives substantial support to the assumption that the population distribution of cadence is approximately normal. A descriptive summary of the data from Minitab follows:

Variable	N	Mean	Median	TrMean	StDev	SEMean
cadence	20	0.9255	0.9300	0.9261	0.0809	0.0181

Variable	Min	Max	Q1	Q3
cadence	0.7800	1.0600	0.8525	0.9600

1. a. Calculate and interpret a 95% confidence interval for population mean cadence.
2. b. Calculate and interpret a 95% prediction interval for the cadence of a single individual randomly selected from this population.
3. c. Calculate an interval that includes at least 99% of the cadences in the population distribution using a confidence level of 95%.