Question

The following data represent the chemistry grades for a random sample of 12 freshmen at a certain college along with their scores on an intelligence test administered while they were still seniors in high school.

Test Chemistry Student Score,
x Grade, y
1 2 3 4 5 6 7 8 9 10 11 12 65 50 55 65 55 70 65 70 55 70 50 55 85 74 76 90 85 87 94 98 81 91 76 74
Compute and interpret the sample correlation coefficient.

Answer 1

R = 0.862

Strong positive relationship

Explanation:

Given the data:

Test Chemistry Student Score,

x Grade, y

1 2 3 4 5 6 7 8 9 10 11 12

Score,x = 65 50 55 65 55 70 65 70 55 70 50 55

Grade, y = 85 74 76 90 85 87 94 98 81 91 76 74

Using technology :

The CORREL function in excel, calculators will give accurate value of the correlation Coefficient between two variables, x and y. The correlation Coefficient obtained using technology is : 0.862

The correlation Coefficient value ranges between (-1 and 1) with values closer to either - 1 or 1 reflecting stronger relationship. A value of 0 means there is no relationship between the variables. Negative values indicate negative relationships while positive indicates positive association between the variables.

Therefore. With a correlation Coefficient of 0.862, the correlation Coefficient can be interpreted as meaning that ; there is a strong positive relationship between score and grade.