Question

A researcher reports that the mean time it takes to complete an experimental task is 1.4 ± 8.0 (M ± SD) s. If the null hypothesis was that the mean equals 1.0, then what is the effect size for this test using estimated Cohen’s d? Group of answer choices

Answer 1

The Cohen's d effect size is 0.05.

Explanation:

The Cohen's d effect size is a numerical value that indicates the standardized difference between two means.

It is provided that the mean time to complete an experimental task reported by the researcher is,

`(\bar x\pm s)=(1.4\pm8.0)`

Since the standard deviation of the population is not provided we will use a one-sample t - test to perform the analysis.

The formula of Cohen's d effect size in case of one-sample t - test is:

`d=(\bar x-\mu)/(s)`

Compute the value of Cohen's d effect size as follows:

`d=(\bar x-\mu)/(s)=(1.4-1.0)/(8)=(0.4)/(8)=0.05`

Thus, the Cohen's d effect size is 0.05.