Question

In a planned study, there is a known population with a normal distribution, μ = 0 , and σ = 5 . What is the predicted effect size (d) if the researchers predict that those given an experimental treatment have a mean of:

      -Question (a): −6

      -Question (b): −10

      -Question (c):  −8

      -Question (d):   0

      -Question (e):  15

Answer 1

a.

Therefore, the following effect size (Cohen's d) is computed as:

Interpretation: The effect size obtained is d = 1.2. According to guidelines specified by Cohen, this corresponds to a large effect size.

b.

Therefore, the following effect size (Cohen's d) is computed as:

Interpretation: The effect size obtained is d = 2 According to guidelines specified by Cohen, this corresponds to a large effect size.

c.

Therefore, the following effect size (Cohen's d) is computed as:

Interpretation: The effect size obtained is d = 1.6. According to guidelines specified by Cohen, this corresponds to a large effect size.

d.

Therefore, the following effect size (Cohen's d) is computed as:

Interpretation: The effect size obtained is d = 0. According to guidelines specified by Cohen, this corresponds to a small effect size.

e.

Therefore, the following effect size (Cohen's d) is computed as:

Interpretation: The effect size obtained is d = 3. According to guidelines specified by Cohen, this corresponds to a large effect size.