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Sample mean = (1.6+5.2+2.8+3.7+4.0)/5 = 3.46
Sample std deviation = sqrt(((1.6-3.46)^2 + ... + (4-3.46)^2 / 5-1) )= 1.35
Z score of 2.8 is (x-mu)/sigma = (2.8-3.46)/1.35 = -0.49
Percentile rank of 2.8 = 20 percentile ( why? out of the 5 numbers it is the 2nd highest number, and therefore will be the upper cutoff for the 20th percentile)
Question 4 3/4 pts Given a sample: 1.6, 5.2, 2.8, 3.7, 4.0 What's the sample mean? 3.46 What's the sample standard deviation? 1.35 decimals) (Round to two What's the z-score for 2.8? 0.49 Round to two decimals) What's the percentile rank (an integer) for 2.8? 20 Answer 1: