The amount of jen's monthly phone bill is normally distributed with a mean of $76 and a standard deviation of $9. what percent of her phone bills are between $49 and $103

To solve this problem, we make use of the z statistic. The formula for z score is:

z = (x - u) / s

where x is sample value, u is the mean and s is the standard deviation

z (x = 49) = (49 - 76) / 9 = - 3

Using the standard tables, P (z = - 3) = 0.0013

z (x = 103) = (103 - 76) / 9 = 3

Using the standard tables, P (z = 3) = 0.9987

Hence,

P (-3 < = z <=3) = 0.9987 - 0.0013 = 0.9974

Therefore 99.74%