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Many studies have suggested that there is a link between exercise and healthy bo

ID: 3309971 • Letter: M

Question

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. 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 mg/cm3 ) was measured.

(a) Make a table giving the sample size, mean, and standard deviation for each group of rats. Consider whether or not it is reasonable to pool the variances. (Round your answers for x, s, and s_(x^^_) [sum of square roots, s x with a line over the x] to one decimal place.)

Group n mean s   s_(x^^_)

Control

Low jump

High jump

(b) Run the analysis of variance. Report the F statistic with its degrees of freedom and P-value. What do you conclude? (Round your test statistic to two decimal places and your P-value to three decimal places.)

F =

P =

Conclusion: There is (a/no) statistically significant difference between the three treatment means at the = .05 level.

Explanation / Answer

from above:

applying one way ANOVA:

b)

from above :

F =8.41

p value =0.001

conclusion: There is a statistically significant difference between the three treatment means at the = .05 level.

Groups n mean s sxbar Control 10 607.4 25.0120 7.9095 Lowjump 10 643.8 24.7377 7.8228 Highjump 10 607 18.8562 5.9628