Question

A researcher records the number of words recalled by students presented with a list of words for one minute. In one group, students were presented with the list of words in color and for the other group, the words were presented in black and white. Test to see if there are differences in the number of words recalled, using alpha = .05 and four steps. Also calculate and interpret effect size and explained variance if appropriate.

Words recalled for B/W condition: 4 5 1 3
Word recalled in color Condition: 7 12 8 11

Answer 1

The question is about conducting a t-test for independent samples to compare the number of words recalled in black and white versus color conditions, followed by calculating effect size and explained variance.

Step-by-step explanation:

The student is asking for assistance with a hypothesis test for differences in means, an alpha level of .05, and the calculation of effect size and explained variance. To test for differences in word recall between the black and white condition and the color condition, we will perform a t-test for independent samples.

1. State the hypotheses. Null hypothesis (H0): μ1 = μ2 (no difference in means). Alternative hypothesis (Ha): μ1 ≠ μ2 (means are different).
2. Calculate the t-statistic and degrees of freedom (df).
3. Determine the critical t-value from the t-distribution table using alpha = .05 and df.
4. Compare the t-statistic to the critical t-value and decide whether to reject H0.

To calculate the effect size, Cohen's d can be used, and the explained variance can be calculated with the r-squared statistic.