Question

Problem # 2 (18 pts). Calculate the correlation coefficient, r, for the data below. 6 8 x Y 4 20 13 3 10 8 7 9 11 13 10 5 12 15 12 4 5 17 A) - 0.778 B) -0.671 C) -0.995 D) - 0.885 Problem # 3 (16 pts). Find the sample standard deviation for the following data set. (Show your work). 22 29 24 24 28 28 25 36 Choose the one choice that best completes the statement or answers the question for standard deviation A) 4.8 these B) 4.2 C) 1.6 D) 2.8. E) None of

Answer 1

Problem 2:

The correlation is -0.995. The following R-commands are used.

> x=c(4,6,13,10,8,7,9,11,12,5)
> y=c(20,15,3,8,12,13,10,5,4,17)
> cor(x,y)
[1] -0.994911

..........................

Problem 3:

R output:

> x=c(22,29,24,24,28,28,25,36)
> sd(x)
[1] 4.375255

So the sample standard deviation (with (n-1) in the denominator of its definition) is 4.37. So I think the correct choice should be option (E), none of the above