Help finding the covariance

label Statistics
account_circle Unassigned
schedule 1 Day
account_balance_wallet $5

A nurse is interested in whether there is a relationship between daily levels of stress and likelihood of a heart attack. The stress scores (predictor variable) and risk of heart attack values (criterion variable) from a small sample of participants are depicted below

Stress Score- 5,2,0,1

Risk of Heart Attack- 1,8,2,5,

What is the covariance?

May 24th, 2015

The covariance is -1.5

This is actually a really bad example because there are so few data points (you would never use a sample size n=4). But, here is the formula:

1/(n-1)Sum(xi-xavg)(yi-yavg), where x=stress and y=risk of heart attack, and n=3 (4-1).

So the means are: 8/4=2; 16/4=4.

1/(3)[(5-2)(1-4)+(2-2)(8-4)+etc]


May 24th, 2015

Studypool's Notebank makes it easy to buy and sell old notes, study guides, reviews, etc.
Click to visit
The Notebank
...
May 24th, 2015
...
May 24th, 2015
Aug 21st, 2017
check_circle
Mark as Final Answer
check_circle
Unmark as Final Answer
check_circle
Final Answer

Secure Information

Content will be erased after question is completed.

check_circle
Final Answer