When constructing a confidence interval for the difference in two ...

[bclement10]

When constructing a confidence interval for the difference in two population means, it is appropriate to use the pooled standard error only when
 a. the population standard deviations can be assumed to be equal.
  b. the sample standard deviations are exactly equal.
  c. the population means can be assumed to be equal.
  d. the sample means are exactly equal.

Question 2

Contradicting some previous research, a new study finds that frequent use of painkillers does not substantially increase a healthy man's risk of developing hypertension. The study finds that the observed difference between the two groups was not statistically significant. Explain in your own words what that means.

[pami445]

Answer to Question 1

A

Answer to Question 2

The sample proportions of men that developed hypertension may actually have been (slightly) different between the two groups, but the relative size of this difference was not large enough to convince us that this may indicate a difference in the population. The (small) difference that was observed was a difference that is observed rather often, if indeed there is no difference between the two groups.

[bclement10]

Thank you!

[pami445]

Always glad to help...