4. Randomly selected people were asked to watch a 1-hour television program. In the middle of the show, a commercial advertising a breakfast cereal appeared. Each person was shown a commercial of a different length ranging from 20 to 48 seconds, with the essential content being the same in all cases. After the show, each person was given a test to determine how much he or she remembered about the product. The commercial times and test scores (on a 20-point scale) are given below: Person 12 3 4 5 6 7 8 Length of commercial(x) 20 24 28 32 36 40 44 48 Test score(y) 10 8 10 11 14 16 12 13 Find the Spearman's rank correlation to conclude if there is any association between the time of exposure and test score. (Use a = 0.10) 6. 05 (15)