MATH 110 Module 9 Exam (Latest-2025) / MATH110 Introduction to Statistics: Portage Learning

5/29/25, 8:29 AM Math 110 - Module 9 Exam




Math 110 - Module 9 Exam
Portage Learning

Question 1

Suppose you have 45 data points and you calculate the sample correlation coefficient and
find that r = 0.32. Can you be 95% confident that a linear relation exists between the
variables? If so, is the relation positive or negative? Justify your answer.


Answer:

For n = 45 and 95% confidence, we get the critical value from the chart:


Critical value: 0.29396
Sample correlation coefficient: |r| = 0.32


Since |r| (0.32) is greater than the critical value (0.29396), a positive linear relation exists
between the variables.




Question 2

Suppose you have 60 data points and you calculate the sample correlation coefficient and
find that r = 0.20. Can you be 95% confident that a linear relation exists between the
variables? If so, is the relation positive or negative? Justify your answer.


Answer:

For n = 60 and 95% confidence, we get the critical value from the chart:


Critical value: 0.25420
Sample correlation coefficient: |r| = 0.20

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