Question

A study of 400 patients hospitalized with diabetes mellitus-related complications shows that serum cholesterol level is a normally distributed variable with a mean of 220 mg/dL and standard deviation of 10 mg/dL. Based on the study results how many patients do you expect to have serum cholesterol ≥ 240 mg/dL in this study? a. 2 b. 10 c. 20 d. 64 e. 128

Answer 1

Solution :

Given that ,

mean = = 220

standard deviation = = 10

P(x 240) = 1 - P(x   240)

= 1 - P((x - ) / (240 - 220) / 10)

= 1 -  P(z 2)  

= 1 - 0.9772

= 0.0228

Probability = 0.0228

patients = 400 * 0.0228 = 9.10 = 10

Option b)