A sample of n=9 individuals is selected from a population with a mean of μ=10. A researcher suspects that after the individuals have gone through a specific type of treatment, their performances on a...

A sample of n=9 individuals is selected from a population with a mean of μ=10.  A researcher suspects that after the individuals have gone through a specific type of treatment, their performances on a standardized examination will be different from the general population. After the treatment, the sample has a
M=13 and s²=9.

1. Using symbols, state the hypothesis for a two-tailed test.


2. Calculate the t statistic and place this on a standardized normal distribution.


3. With a two-tail α=0.05, state the conclusion of these findings.


4. Calculate the estimated d and state the effect size (i.e., small, medium, large).