A researcher would like to know if memory function changes significantly from the first testing session (Mem1) to the second testing session (Mem2). Perform a two-tailed t-test with = .05 to answer the following question:

Does memory performance change significantly from the first session to the second?

A. What type of t-test should be performed to answer this question? What is your rationale?

A two-tailed paired sample t-test should be performed. We are testing the memory performance of the same individuals (same samples) in two different sessions (MEM1 and MEM2) resulting in paired observations. The paired sample t-test will help determine if there is a statistically significant difference in memory performance betweenthe first session and the second session.

B. Create the null hypothesis from the research question.

Null hypothesis (H0) : There is no significant change in memory performance from the first session to the second session

C. Run the analysis in SPSS and answer the following questions based on the analysis results. (Paste all the output tables from SPSS for this test. No points will be earned for the rest of the questions in Q2 if the output tables are not pasted or are incomplete).

Paired Samples Statistics
	Mean	N	Std. Deviation	Std. Error Mean
Pair 1	Mem1	100.7910	50	9.47627	1.34015
Mem2	95.5574	50	9.81464	1.38800

Paired Samples Correlations
	N	Correlation	Significance
One-Sided p	Two-Sided p
Pair 1	Mem1 & Mem2	50	.867	<.001	<.001

D. Use the SPSS output to determine the effect size, Cohen's d,and explain what the effect size means in this context. Effect size must show in the SPSS table. Do not round, report all decimals from the table. (Note: It is OK if d is negative. But it needs to be consistent with the sign of t statistic.???

The effect size, Cohen's d, is 1.051.

In this context, the effect size means that the difference in memory performance between the first and second sessions is approximately 1.05 standard deviations. This is a measure of the magnitude of the difference between the two groups. It is considered a large effect size, suggesting a significant difference in memory performance between the two sessions.

E. Report the t-test result in symbols according to the APA standards, including t statistic with degree of freedom, p-value, and effect size d.

The t-test result in symbols according to the APA standards:

t(49) = 7.428, p < .001, d = 1.051

F. What is your decision about the null hypothesis (reject or fail to reject)? What is your rationale?

My decision about the null hypothesis is to reject it. The rationale for this decision is that the p-value is less than the significance level of 0.05, indicating that the difference in memory performance from the first session to the second is statistically significant.

G. What is the answer to the research question?

Research question: Does memory performance change significantly from the first session to the second?

Yes. Memory performance does change significantly from the first session to the second. The mean difference between the two sessions is 5.23360, with memory performance in the first session being higher than in the second session.

SubID	Gender	Educ	Age	Mem1	Mem2
1	1	1	65.8	100.43	91.63
2	1	0	66.9	87	90
3	1	0	76.9	87	90
4	1	0	79.9	85.77	70
5	1	0	67.5	93.4	90.27
6	1	0	84.1	102.19	101.34
7	1	0	72.6	98.31	88.2
8	2	1	75.6	112.2	105.71
9	2	0	82.6	109.89	94.76
10	1	0	78	104.75	95.03
11	2	0	66.3	102.19	99.37
12	2	0	65.1	93.7	84.29
13	2	1	67.2	101.3	97.49
14	2	0	70	106.59	99.37
15	2	1	80	84.34	86.44
16	2	0	69.4	99.12	86.93
17	2	0	65.3	107.04	100.36
18	2	1	70.6	94.42	91.44
19	2	0	78.4	112.8	103.91
20	2	1	69.6	93.83	92.43
21	2	1	65.8	102.6	96.34
22	2	0	75	81.45	69.25
23	2	0	68.5	103.55	94.07
24	1	1	69.5	93.13	81.43
25	1	1	67	114.53	112.87
26	2	0	69.9	108.73	102.84
27	2	1	86.6	95.89	94.9
28	2	1	66.1	80.11	80.88
29	1	0	65.2	92.13	91.85
30	2	0	76.8	111.96	106.24
31	1	0	75.4	106.01	102.08
32	2	1	66.7	113.34	101.89
33	2	0	65.5	110.51	110.02
34	2	1	72.8	102.92	100.72
35	2	1	79.5	100.49	93.43
36	2	0	72.9	108.46	101.21
37	2	1	69.7	115.03	105.08
38	1	1	66	102.62	100.3
39	1	1	71.4	100	103.97
40	1	1	75.8	110.02	111.17
41	1	1	65.4	85.77	74.28
42	2	1	67	97.02	96.76
43	2	1	79.2	108.46	95.26
44	1	1	69.3	101.39	100.42
45	1	1	68.1	83.58	82.74
46	2	0	77.5	107.63	105.91
47	1	1	67.8	99.51	93.98
48	2	1	73	104.82	101.21
49	1	1	71.9	107.02	99.62
50	2	0	68.3	114.6	108.18