Question

Use the following to answer questions.

Two separate tests are designed to measure a student's ability to solve problems. Several students are randomly selected to take both tests and the results are given below.

Test A 64 48 51 59 60 43 41 42 35 50 45

Test B 91 68 80 92 91 67 65 67 56 78 71

1. What is the value of the linear coefficient r?

** i got .974

2. Assuming a 0.05 level of significance, what is the critical value? ** not sure about my answer for this one

3. What do you conclude about the correlation of the variable?

4. What's the slope of regression line? *i got 1.32

5. whats the yintercept of regression line? *i got 10.59

6. what is the percent of explained variation determined by the regression line? **not sure about my answer for this one either, i got 90%

please show steps thanks! :))

Answer 1

Using Excel

data -> data analysis -> regression

1)
r = 0.974
2)

critical r = 0.602 for n = 11 and alpha = 0.05

3)

since r > critical r

we reject the null hypothesis

4)
slope = 1.32

5)
intercept = 10.59

6)
R^2 = r^2 = 0.974^2 = 0.9496
94.96 % of variation is explained..

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