Exam One

PSYC 1000, Exam 1, February, 2008

To determine your current standing in the class, you should take your exam score (posted in BlackBoard) and add five points if you have completed one unit of research participation. If you have completed two units of research participation (one required, one for extra credit), add ten points to your score in BlackBoard. If that yields 90 or more, you have an A, 80 or more a B, 70 or more a C, 60 or more a D, below 60 an F.

Here are some statistics on distribution of grades. In computing these statistics I have assumed that every student has earned one research participation credit (worth five points).

**Grade**
		Frequency	Percent	Valid Percent
Valid	A	16	17.6	18.0
	B	22	24.2	24.7
	C	19	20.9	21.3
	D	16	17.6	18.0
	F	16	17.6	18.0
	Total	89	97.8	100.0
Missing	Inc	2	2.2
Total		91	100.0

Median	76.00
Std. Deviation	21.678
Skewness	-1.606
Minimum	5
Maximum	100

Quick Summary

Half the students got a 76 or better.
The scores ranged from 5 to 100.
A few very low scores resulted in the distribution having great negative skewness.
The most frequent grade was a B.

Does Taking the Practice Tests Help?
BlackBoard keeps track of who has and who has not taken the practice tests that I made available to you online. I do not use this information for grading purposes, but I was curious about whether or not taking those practice tests was associated with performance on the exam. Here are some analyses that address that question.

**Chapter 1 Practice Test**
	Chapter1	N	Mean	Std. Deviation
Exam_1	0= did not take	43	64.84	24.738
Exam_1	1= did take	46	78.28	16.079

**Independent Samples Test**
		Levene's Test for Equality of Variances		t-test for Equality of Means
		t	df	Sig. (2-tailed)	Mean Difference
Exam_1	Equal variances not assumed	-3.018	71.338	.004	-13.445

On average, those who took the Chapter 1 practice test scored 13.4 points higher than those who did not. This difference is statistically significant. A little more than half of the students took this practice test.

**Chapter 2 Practice Test**
	Chapter2	N	Mean	Std. Deviation
Exam_1	0= did not take	70	68.84	22.897
Exam_1	1= did take	19	82.63	11.393

**Independent Samples Test**
		Levene's Test for Equality of Variances		t-test for Equality of Means
		t	df	Sig. (2-tailed)	Mean Difference
Exam_1	Equal variances not assumed	-3.644	60.221	.001	-13.789

On average, those who took the Chapter 2 practice test scored 13.8 points higher than those who did not. This difference is statistically significant. Only 19 of 89 students took this practice test.

**Chapter 3 Practice Test**
	Chapter3	N	Mean	Std. Deviation
Exam_1	0= did not take	76	69.36	22.234
Exam_1	1= did take	13	86.00	10.000

**Independent Samples Test**
		Levene's Test for Equality of Variances		t-test for Equality of Means
		t	df	Sig. (2-tailed)	Mean Difference
Exam_1	Equal variances not assumed	-4.418	36.679	.000	-16.645

On average, those who took the Chapter 3 practice test scored 16.6 points higher than those who did not. This difference is statistically significant. Only 13 of 89 students took this practice test.