#1- The normal distribution had a mean of 14 and standard deviation of 4. There were 30 people in the study group and the average was expected to be 16. The study was tested at the .05 level of significance. What was the power of the study?

74.2%
80.5%
86.4%
92.7%

#2- If a sample with a mean of 60 has an estimated effect size of 2, is that effect size small, medium, or large?

To calculate the power of the study, we need to use the information provided: the mean, standard deviation, sample size, expected average, and the significance level.

#1 - Power of the Study:
To calculate the power of the study, we can use statistical calculations or tables. In this case, since we have the mean, standard deviation, sample size, and expected average, we can use a calculator or software to determine the power.

To do this, we need to know the effect size and the significance level. However, the effect size is not provided in the given information, so we cannot calculate the power accurately. Without the effect size, we cannot determine the power.

Therefore, we cannot provide an accurate answer for the power of the study.

#2 - Effect Size:
Effect size is a measure of the magnitude of the difference or relationship between variables. It helps us determine the practical or theoretical importance of an observed effect.

In statistics, effect size is commonly measured using Cohen's d, which is the difference between the means divided by the standard deviation. Cohen's d of 0.2 is considered small, 0.5 is considered medium, and 0.8 or larger is considered large.

For your question, an estimated effect size of 2 is considered large based on traditional guidelines for Cohen's d.

Therefore, the effect size is large.

Please note that this answer is based on the traditional guidelines for Cohen's d and may vary depending on the context or field of study.