Question

A school counselor records the number of outbursts in a sample of different classrooms at a local school. This is what they reported: "The number of outbursts among students at this local school (M = 3) were significantly less than that in the general population, z(n=36) = 2.19, p = .0143, d = .75, large effect, 95% CI [3.36, 5.08]." Based on this statement, answer the following questions:

What is the sample size?
What is the decision (fail to reject or reject the null hypothesis? What specific information helped you answer this question?
What is the effect size in this study?
Interpret effect size (how likely is it that we will get the same results if we obtain different samples)?

Answer 1

The sample size is 36. We reject the null hypothesis because the p-value is .0143, indicating significant difference. The effect size d=.75 suggests a high likelihood of getting similar results with different samples.

Step-by-step explanation:

The sample size from the given statement is n=36. This is the number of classrooms in the counselor's sample. To make a decision about the null hypothesis, we look at the p-value which is p=.0143.

Since the p-value is less than the commonly used alpha level of 0.05, we reject the null hypothesis. This indicates that the number of outbursts in the sample of classrooms is significantly different from the general population. The

effect size

for this study is d=.75, which is considered a large effect size according to Cohen's standards. This large effect size suggests that the difference in the number of outbursts between the sample and the general population is substantial. When it comes to interpreting this effect size, it means that if different samples were taken, there's a higher likelihood of getting the same results considering the effect size indicates a meaningful difference between the groups.