The patient recovery time from a particular surgical procedure is normally distributed with a mean of 5.3 and a standard deviation of 2.1 days. The 90th percentile for recovery time is?

Answer 1

Z score for 90th percentile is 1.28

Z = (X-mean)/standard deviation

1.28 = (X-5.3)/2.1

X - 5.3 = 2.69

X = 7.99 = about 8 days for recovery