Correlation Between Grade (Total Points) and Attendance

Topic Classification: Descriptive statistics, correlation

Applicable Courses: MAT 114, 155, STA 270

Proposer: Dr. Kathryn Cruz-Uribe, Department of Anthropology,

Northern Arizona University

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The attached data can be used to explore the linear relationship between grades and attendance in an introductory level large lecture class. The variable “attendance” can range from 0 to 20 points. Attendance is taken 20 times during the semester—if the student is there all 20 times, she gets 20 points, if she is there 15 times, she gets 15 points, etc. The variable “total points” is the non-attendance points earned in the class. So, these are points earned on quizzes, tests, exercises and assignments. Total points can range from 0 to 275, and translate directly into grades (above 90% is an A, above 80% a B, etc.)

This can lead into an interesting discussion about issues of “correlation” vs. “causation.” Do the students with high attendance earn higher grades because they attend class and thus learn the material better, or is it simply a matter that the better students attend class more regularly? Or both?

The attached data is actual data from a Spring 2001 class. Use this data to answer the following questions.

1. First, glance at the data. Do total points appear to be related to attendance points?
2. Compute the Pearson correlation coefficient using technology. How strong is the linear relationship?
3. Create a scatterplot with the regression line plotted. What are the total points that the regression line would predict for someone with 5 absences?
4. Describe your interpretation of the relationship. In particular, does the correlation coefficient indicate that high attendance causes higher grades? Could there be another root cause?

Your report should be expressed in paragraph form. Be sure to indicate the context and describe the objectives. Include supporting charts and computations properly labeled.

Attendance	Total Points	Attendance	Total Points	Attendance	Total Points
13	137	18	233	14	157.5
16	189	14	145	16	198
17	213.5	17	143	14	158.5
20	250	17	230.5	17	157.5
20	191	19	213	18	185.5
20	245.5	19	181.5	17	209
16	171.5	20	237.5	19	233
10	164.5	18	207	17	226.5
18	220	17	195.5	3	38.5
12	99	15	134.5	16	232.5
20	196	13	119.5	19	212
18	222	9	171.5	19	195.5
20	223	16	148	19	256
20	237	20	247.5	17	235.5
17	228.5	13	179.5	18	185
15	185.5	17	230	14	193.5
14	205	15	196	17	203
17	175	15	193	19	249.5
17	163	0	20	11	84
13	179.5	20	229.5	16	220
14	163	19	198	18	203
20	239	15	176.5	17	175
19	192	19	183.5	18	166
20	258	18	218.5	16	165.5
10	182.5	19	208.5	15	180
17	197	20	243.5	19	203.5
19	249	18	220	18	165.5
19	208	18	199.5	19	188.5
17	208	20	247.5	15	175
15	178	17	194.5	15	221
19	232	8	58	20	237.5
13	178.5	7	150	17	174.5
19	186.5	19	214	19	222
12	228	19	245	20	256.5
20	242.5	16	129	16	222
10	100	12	220.5	17	242
17	180	17	220	18	230
20	239.5	19	233

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Produced for NSF CCLI Grant # 9980883 "Enhancing Quantitative Reasoning Using Visualization".
Copyright: Kathryn Cruz-Uribe and Janet McShane, 2001

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