Question

Instructions:To make sure you have all the data you need to calculate the effect size, here are the means and standard deviations for the "hit" and "smashed into" groups from last week.

Group Responses to Car Speed Hit v. Smashed

Hit Group	Smashed Into Group
32	50
26	44
40	54
23	45
42	44
20	40
37	49
25	34
24	38
22	30
19	50
24	46
19	40
22	35
29	43
24	41
34	30
33	39
37	44
20	35

Group #1: Smashed into mean and SD: Mean = 41.55, Variance = 44.15, SD = 6.64

Group #2: Hit mean and SD:   M = 27.6, Variance = 53.94, SD = 7.34

1) Compute the effect size (Cohen’s d using the pooled variance). Which of the following is the effect size? Round 2 decimal points.

Group of answer choices

A. Cohen’s d =1.99

B. Cohen’s d =2.13

C. Cohen’s d =1.12

D. Cohen’s d =2.10

2) What does the pooled Cohen’s d you obtained using the coin study data represent?

A. A small/weak effect

B. No effect

C. A medium/moderate effect

D. A large effect

3) What is the effect size and why do we report it?

4) When is it appropriate to use a dependent samples t-Test?

A. Participants are of different gender

B. Participants are recruited after completing a screening questionnaire

C. Participants are randomly assigned to a group

D. Participants provide more than one score or they are matched

5) Results Section write up: Cognitive ability of participants before and after participants consumed alcohol was recorded. Results showed a significant difference in cognitive ability before and after alcohol consumption, t(28) = 4.89, p < .01. Participants had higher scores on the cognitive task before they consumed alcohol (M = 4.55, SD = 1.11) than after (M = 2.22, SD = .09).

Using the write up of the results section from an APA empirical research article, identify which test was conducted?

A. Pearson correlation

B. Independent sample t-test

C. Dependent sample t-test

D. z-test

6) Results Section write up: Differences between treatment and control groups were tested. Results showed a significant difference between groups, t(38) = 3.45, p < .01. Participants in the treatment condition, who received study materials, had significantly higher GRE scores (M = 4.55, SD = 1.11) than participants in the control condition, who did not receive study materials (M = 2.22, SD = .09).

Using the write up of the results section from an APA empirical research article, identify which test was conducted?

A. Pearson correlation

B. Independent sample t-test

C. Dependent sample t-test

D. z-test

Answer 1

## instructions:To make sure you have all the data you need to calculate the effect size, here are the means and standard deviations for the "hit" and "smashed into" groups from last week.

## Group #1: Smashed into mean and SD: Mean = 41.55, Variance = 44.15, SD = 6.64

Group #2: Hit mean and SD:   M = 27.6, Variance = 53.94, SD = 7.34

## Q 1) Compute the effect size (Cohen’s d using the pooled variance). Which of the following is the effect size? Round 2 decimal points.

Group of answer choices

Answer : A. Cohen’s d =1.99

## Q 2)  What does the pooled Cohen’s d you obtained using the coin study data represent?

Answer : B. No effect

## Q 3) What is the effect size and why do we report it?

Answer : Effect size is a quantitative measures of the magnitude of the experimenter effect . The larger the effct size the stronger the realtionship between two variables ,

why do we report it : we have to find out what type of relationship between two variables .

and it can be used to quantitatively compare the result of studies done in different settings

## 4) When is it appropriate to use a dependent samples t-Test?

Answer : D. Participants provide more than one score or they are matched

## 5) Results Section write up: Cognitive ability of participants before and after participants consumed alcohol was recorded. Results showed a significant difference in cognitive ability before and after alcohol consumption, t(28) = 4.89, p < .01. Participants had higher scores on the cognitive task before they consumed alcohol (M = 4.55, SD = 1.11) than after (M = 2.22, SD = .09).

Using the write up of the results section from an APA empirical research article, identify which test was conducted?

Answer : C. Dependent sample t-test

## 6) Results Section write up: Differences between treatment and control groups were tested. Results showed a significant difference between groups, t(38) = 3.45, p < .01. Participants in the treatment condition, who received study materials, had significantly higher GRE scores (M = 4.55, SD = 1.11) than participants in the control condition, who did not receive study materials (M = 2.22, SD = .09).

Using the write up of the results section from an APA empirical research article, identify which test was conducted?

Answer : B. Independent sample t-test