In: Statistics and Probability
Consider the following sample data:
x 21 22 25 28 24
y 15 22 26 28 29
a. Calculate the covariance between the variables. (Negative value should be indicated by a minus sign. Round your intermediate calculations to at least 4 decimal places and final answer to 2 decimal places.)
b. Calculate the correlation coefficient. (Round your intermediate calculations to 4 decimal places and final answer to 2 decimal places.)
x | y | X*Y | X2 | Y2 |
21.00 | 15.00 | 315.00 | 441.00 | 225.00 |
22.00 | 22.00 | 484.00 | 484.00 | 484.00 |
25.00 | 26.00 | 650.00 | 625.00 | 676.00 |
28.00 | 28.00 | 784.00 | 784.00 | 784.00 |
24.00 | 29.00 | 696.00 | 576.00 | 841.00 |
120.00 | 120.00 | 2,929.00 | 2,910.00 | 3,010.00 |
Correlation Calculations | |||
Answer | Answer | ||
n | 5.0000 | SSxx | 30.0000 |
∑Xi | 120.0000 | SSyy | 130.0000 |
X bar | 24.0000 | SSxy | 49.0000 |
∑Yi | 120.0000 | ||
Y bar | 24.0000 | Correlation r | 0.7846 |
∑Xi*Yi | 2929.0000 | ||
X2 | 2910.0000 | ||
Y2 | 3010.0000 |
Based on the above table, the
following is calculated: Now, the covariance between X and Y is computed using the following expression: b. Therefore, based on this information, the sample correlation coefficient is computed as follows:
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