The data from Exercises 2.15 and 2.16 come from the same 10 (N) observers. In other words, the same person had a score of 1.65 in the Eyes Level condition and 1.73 in the Eyes Elevated condition. Therefore, the data form pairs of scores.
(a) Multiply the scores in each pair together to get a variable called XY.
(b) Calculate ΣXY.
(c) Calculate ΣXΣY.
(d) Do ΣXY and ΣXΣY differ, and would you normally expect them to?
(e) Calculate

(You will come across these calculations again in Chapter 9. The result is called the covariance.
Very few of the calculations in this book will be any more complex than this one.)

Transcribed Image Text:

ΣΧΣΥ ΣΧΥ