Question

The Graduate Management Aptitude Test (GMAT), produced by the Educational Testing Service (ETS) in Princeton, New Jersey, is widely used by graduate schools of business in the U.S. as an entrance requirement. Assume that the scores in a recent year are normally distributed with a mean of 494 and a variance of 10,000.

What is the probability that a randomly selected score is greater than 384?

Answer 1

Solution :

Given that ,

mean = = 494

variance = ² = 10000

standard deviation = = 100

P(x > 384) = 1 - P(x < 384)

= 1 - P((x - ) / < (384 - 494) / 100)

= 1 - P(z < -1.1)   Using standard normal table,

= 1 - 0.1357   

= 0.8643

P(x > 384) = 0.8643

Probability = 0.8643