Question

Height (inches)	Running Speed (Seconds)
60	8
55	11
56	10
52	12
48	14
44	16
47	13
52	12

The attached spreadsheet contains data from a random sample of eight elementary school children. Each child was measured for height (in inches) and timed in the 40-yard dash (in seconds).

What is z' for the correlation between height and speed in this sample?

(Give your answer to at least 3 decimal places)

Answer 1

X Values
∑ = 414
Mean = 51.75
∑(X - Mx)2 = SSx = 193.5

Y Values
∑ = 96
Mean = 12
∑(Y - My)2 = SSy = 42

X and Y Combined
N = 8
∑(X - Mx)(Y - My) = -88

R Calculation
r = ∑((X - My)(Y - Mx)) / √((SSx)(SSy))

r = -88 / √((193.5)(42)) = -0.976

correlation coefficient = -0.976