In forecasting and prediction in public health a vital concern is this: before a safe and effective vaccine is available what will be the total number of coronavirus infections in the U.S.? Consider the following discrete probability distribution with five "scenarios". The values for the random variable: X = total Covid19 infections (in millions). Calculate the critical summary statistics for this probability distribution:
Xi P(Xi)
10 0.15
15 0.30
20 0.35
25 0.20
30 0.10
[Q] What is the Standard Deviation for X, σX= ?
(a) 6.372 (b) 7.155 (c) 7.677 (d) 8.25 (e) 8.88