Question

Given a normal distribution with Mean of 100 and Standard deviation of 10, what is the probability that

between what two X values (symmetrically distributed around the mean) are 80% of the values?

Answer 1

Mean= 100

Std= 10

Data will be distributed equally on both sides of the mean. mean= 0.5

So, the probability is divided by 2 = 0.8/2 =0.4

Minimum value:

Where Z(0.1) = -1.282

Maximum value:

Z(0.9)= 1.282