Exercise and healthy bones. Many studies have suggested that there is a link between exercise and healthy bones. Exercise stresses the bones and this causes them to get stronger. One study examined the effect of jumping on the bone density of growing rats.16 There were three treatments: a control with no jumping, a low-jump condition (the jump height was 30 centimeters), and a high-jump condition (60 centimeters). After 8 weeks of 10 jumps per day, 5 days per week, the bone density of the rats (expressed in milligrams per cubic centimeter) was measured. Here are the data:
(a) Make a table giving the sample size, mean, and standard deviation for each group of rats. Is it reasonable to pool the variances?
(b) Run the analysis of variance. Report the F statistic with its degrees of freedom and P-value. What do you conclude?