Many studies have suggested that there is a link betweenexercise and healthy bones. Exercise stresses the bones and thiscauses them to get stronger. One study examined the effect ofjumping on the bone density of growing rats. There were threetreatments: a control with no jumping, a low-jump condition (thejump height was 30 centimeters), and a high-jump condition (60centimeters). After 8 weeks of 10 jumps per day, 5 days per week,the bone density of the rats (expressed in mg/cm3 ) was measured.Here are the data. data126.dat
(a) Make a table giving the sample size, mean, and standarddeviation for each group of rats. Consider whether or not it isreasonable to pool the variances. (Round your answers for x, s, ands_(x^^\_) to one decimal place.)
Group n x^^\_ s s_(x^^\_)
Control
Low jump
High jump
(b) Run the analysis of variance. Report the F statistic withits degrees of freedom and P-value. What do you conclude? (Roundyour test statistic to two decimal places and your P-value to threedecimal places.)
F =
P =
Conclusion: There is no? or a? statistically significantdifference between the three treatment means at the ? = .05level.
obs group g density1 Control 1 5652 Control 1 5983 Control 1 6114 Control 1 6015 Control 1 6236 Control 1 6077 Control 1 5958 Control 1 6499 Control 1 62010 Control 1 57611 Lowjump 2 62912 Lowjump 2 64513 Lowjump 2 62614 Lowjump 2 65315 Lowjump 2 63316 Lowjump 2 63917 Lowjump 2 62418 Lowjump 2 63919 Lowjump 2 64320 Lowjump 2 62221 Highjump 3 61922 Highjump 3 61423 Highjump 3 60624 Highjump 3 60825 Highjump 3 61526 Highjump 3 60827 Highjump 3 62028 Highjump 3 61929 Highjump 3 59730 Highjump 3 593
