Question

If z is a standard normal variable, find the probability. the probability that z lies between -2.41 and 0

Answer 1

To solve this problem, what we can do first is to find for the value of probability (p value) using the standard distribution tables for z. Looking at the table, we can see that the p values are:

 

when z = - 2.41:

p value = P (z = - 2.41) = 0.0080

 

when z = 0:

p value = P (z = 0) =  0.5000

 

The probability that z lies between – 2.41 and 0 is the difference of the two probabilities, with the bigger probability subtracted by the smaller probability. That is:

 

P (0 ≥ z ≥ -2.41) = 0.5000 - 0.0080

P (0 ≥ z ≥ -2.41) = 0.4920