In: Statistics and Probability
A study was conducted to determine whether the final grade of a student in an introductory psychology course is linearly related to his or her performance on the verbal ability test administered before college entrance. The verbal scores and final grades for 10 students are shown in the table below.
Student | Verbal Score xx | Final Grade yy |
1 | 35 | 91 |
2 | 64 | 74 |
3 | 46 | 61 |
4 | 35 | 98 |
5 | 79 | 95 |
6 | 53 | 88 |
7 | 63 | 83 |
8 | 54 | 98 |
9 | 37 | 99 |
10 | 42 | 72 |
Find the following:
The least squares line: ŷ =
Calculate the residual for the second student:
The following data are passed:
X | Y |
35 | 91 |
64 | 74 |
46 | 61 |
35 | 98 |
79 | 95 |
53 | 88 |
63 | 83 |
54 | 98 |
37 | 99 |
42 | 72 |
The independent variable is X, and the dependent variable is Y. In order to compute the regression coefficients, the following table needs to be used:
X | Y | X*Y | X2 | Y2 | |
35 | 91 | 3185 | 1225 | 8281 | |
64 | 74 | 4736 | 4096 | 5476 | |
46 | 61 | 2806 | 2116 | 3721 | |
35 | 98 | 3430 | 1225 | 9604 | |
79 | 95 | 7505 | 6241 | 9025 | |
53 | 88 | 4664 | 2809 | 7744 | |
63 | 83 | 5229 | 3969 | 6889 | |
54 | 98 | 5292 | 2916 | 9604 | |
37 | 99 | 3663 | 1369 | 9801 | |
42 | 72 | 3024 | 1764 | 5184 | |
Sum = | 508 | 859 | 43534 | 27730 | 75329 |
Based on the above table, the following is calculated:
Therefore, based on the above calculations, the regression coefficients (the slope m, and the y-intercept n) are obtained as follows:
Therefore, we find that the regression equation is:
Second Student
When X = 64
Residual for the second student is:
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