The poppingtimes of the kernels in a certain brand of microw

The popping-times of the kernels in a certain brand of microwave popcorn are normally distributed with a mean of 150 seconds and a standard deviation of 10 seconds. The first kernel pops 127 seconds after the microwave oven is started What is the z-score of this kernel? A. 2.30 B 0.43 C. -2.30 D -0.43

Solution

mean, m = 150

std. deviation = 10

x = 127

z acore = (x - m)/std deviation = ( 127 - 150)/10 = -23/10 = -2.3

Option c