Question

Problem 4. A researcher is comparing the effectiveness of two sets of instructions for assembling a book shelf A sample of 24 college students is obtained, and each participant is randomly assigned to one of the two groups. Half of the participants (n 12) are given both written and graphic instructions ("Written Graphic"), and the other half (n= 12) receives written instructions only ("Written"). The researcher measures how much time is needed for each participant to assemble the book shelf The scores are the number of minutes needed by each participant. Is there a significant mean difference in the assembly time between the two groups? Use a two-tailed test with a= .05. Written_Graphic Written 20 15 10 22 30 26 19 18 23 24 25 17 30 22 25 35 26 36 40 28 33 35 28 32 or t-test for dependent (1 point) What statistics (one-sample t-test, t-test for two samples) would you use to test the hypothesis? Provide your justification. b. (1 point) Put the SPSS output (two tables). (0.5 points) Calculate d Show me all the steps you follow to get d so that I can give you a partial credit when your answer is incorrect d. (2 points) Make a conclusion with APA format, including interpretation of d independent samples, a. C.

Answer 1

Answer:

a).

t test for two independent sample to be used because Two different groups are compared.

b).

Group Statistics
	Group	N	Mean	Std. Deviation	Std. Error Mean
time	Written Graphic	12	20.7500	5.41253	1.56246
	Written	12	30.8333	5.25415	1.51674

Independent Samples Test
		Levene's Test for Equality of Variances		t-test for Equality of Means
		F	Sig.	t	df	Sig. (2-tailed)	Mean Difference	Std. Error Difference	95% Confidence Interval of the Difference
									Lower	Upper
time	Equal variances assumed	.005	.944	-4.631	22	.000	-10.08333	2.17757	-14.59933	-5.56734
	Equal variances not assumed			-4.631	21.981	.000	-10.08333	2.17757	-14.59956	-5.56711

c).

cohen d = (30.8333-20.75)/sqrt((5.41253^2+5.25415^2)/2)

=1.89041

d).

The 12 participants in the Written Graphic group (M = 20.8, SD = 5.4) and the 12 participants in the Written group (M = 30.8, SD = 5.3), demonstrated a significant difference in time taken (t[22] = -4.63, p < .01), d=1.89.