Normal Distribution Test

Most graduate schools of business require applicants for admission to take the Graduate Management Admission Council’s GMAT examination. Scores on the GMAT are roughly normally distributed with a mean of 527 and a standard deviation of 112. What is the probability of an individual scoring above 500 on the GMAT?

• 0.4052

• 0.5948

• -0.24

Answer explanation

P{Z > -0.24} = 1 – 0.4052 = 0.5948

The length of human pregnancies from conception to birth approximates a normal distribution with a mean of 266 days and a standard deviation of 16 days. What proportion of all pregnancies will last between 240 and 270 days (roughly between 8 and 9 months)?

• 0.5471

• 0.5987

• 0.0516

• -1.63

Answer explanation

P(-1.63 < Z < 0.25) = 0.5987 – 0.0516 = 0.5471

Find the z-score if x = 33, the mean = 45 with a standard deviation of 5.

• -2.4

• 1.2

• 2.4

• -1.2

Answer explanation

(33-45)/5 = -2.4

The weights of adult male beagles are normally distributed, with a mean of 25 pounds and a standard deviation of 3 pounds. A beagle is randomly selected. Find the probability that the beagle's weight is less than 23 pounds.

• -0.67

• 0.7486

• 0.2514

Answer explanation

Less than is to the left. Look up -.67 and you get .2514.

Find the z-score for the following data.

x = 21,000

mu = 25,000

sigma = 1,250

• -3.21

• 3.2

• 3.1

• -3.2

Answer explanation

(21000-25000)/1250

The weights of adult male beagles are normally distributed, with a mean of 25 pounds and a standard deviation of 3 pounds. A beagle is randomly selected. Find the probability that the beagle's weight is more than 30 pounds.

• .9525

• .0475

• 1.67

• .0575

Answer explanation

1-.9525 = .0475

434 Company pack coffee in bags marked as 250 g

A large number of packs of coffee were weighed and the mean and standard deviation were calculated as 255 g and 2.5 g respectively.

Assuming this data is normally distributed, what percentage of packs are underweight?

• 2.5%

• 3.5%

• 4%

• 5%

The ages of the population of people living in Meru area in Ipoh are Normally distributed with mean 43 and standard deviation 14

The town has a population of 5,000.

How many would you expect to be aged between 22 and 57?

You can use this Standard Normal Distribution curve:

• 1750

• 3860

• 3870

• 4330

If the value we are looking for is smaller than the mean, the value of z is:

• Not enough information

• Negative

• Positive

• 0

If the value we are looking for is the same as the mean, the value of z is:

• Not enough information

• Positive

• Negative

• 0