Question

Which of the following probabilities is the greatest for a standard normal distribution?

A. P(-1.5≤z≤-0.5)
B. P(-0.5≤z≤0.5)
C. P(0.5≤z≤1.5)
D. P(1.5≤z≤2.5)

Answer 1

This can be found by using a standard normal distribution table, such as the table here:
http://www.math.bgu.ac.il/~ngur/Teaching/probability/normal.pdf

Answer 2

If we take option A, from the table we find:
cumulative probability for z = -1.5 is 0.0668
cumulative probability for z = -0.5 is 0.3085
Therefore P(-1.5≤z≤-0.5) = 0.3085 - 0.0668 = 0.2417
Now you need to repeat this process for the other answer options to find the greatest probability.

Answer 3

Ohhh, I see. How would I find it for 2.5?

Answer 4

Just look it up in the table that I gave you a link to.

Answer 5

Would it be B?

Answer 6

You need to calculate the probability for each of the options.

Answer 7

B came out to be 0.2909. I just want to know if I'm right?

Answer 8

Your calculation for B is not correct.
cumulative probability for z = 0.5 is 0.6915
cumulative probability for z = -0.5 is 0.3085
Therefore P(-0.5≤z≤0.5) = 0.6915 - 0.3085 = 0.383