Chapter 9.3, Problem 97E

To determine

To explain: Reason for this result is statistically significant, but not practically important.

Answer to Problem 97E

The result given in statistically significant but not practically important as this increase of only two points on the SAT is not that so big deal.

Explanation of Solution

Given information:

Hypotheses,

  $H0:\mu =128$

  $Ha:\mu >128$

  $\overline{x}=130$

  $t=2.18$

  $S_x=65$

  $\alpha =0.0148$

The result given in statistically significant but not practically important as this increase of only two points on the SAT is not that so big deal.

When null hypothesis can be rejected at the usual levels $\alpha =0.05or\alpha =0.01$ , there is good evidence of a difference, but difference might be small.

When large samples are available, even so small deviations from the null hypothesis will be significant.