Normal Probabilities

Find the area under the normal distribution curve between a z=-1.26 and z=.57. 

• 0.0047

• 0.9204

• 0.6119

• 0.4981

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 24 pounds.

• 0.3694

• 0.3781

• 0.0912

The test scores for the exam in statistics class have a mean of 78 points and standard deviation of 9 points. A student is randomly selected. Assuming the scores are normally distributed find the probability that the score is more than 95. 

• 0.0295

• 0.00000005

• 0.3209

• 4.32

μ = 350 , σ = 20 , find P(X > 400)

• 0.0062

• 0.9938

• 0.4013

• 0.5987

A continuous random variable is normally distributed with mean 145 and standard deviation is 5. Find P(136<X<140).

• 0.8054

• 0.8772

• 0.1228

• 0.1587

The heights of male students are Normally distributed with mean 1.7 m and standard deviation 0.2 m

In a population of 400 male students, how many would you expect to have a height between 1.4 m and 1.6 m?

• 24

• 54

• 97

• 100

According to the normal distribution, what percent of the population has an IQ between 70 -115

• 68%

• 81.5%

• 95%

• 47%

The normal distribution curves represents U.S. female heights. What percentage of females are between 5'6.5" and 5'11"?

• 68%

• 95%

• 16%

• 81%

The number of accidents per week, in a company, is normally distributed with a mean of 6.4 with a standard deviation of 1.5.  What proportion of weeks would you expect to have more than 7 accidents?

• 0.3446

• 0.2856

• 0.4

• 0.6554

What's the probability of 49 < x < 51 ?

(Mean = 50, Standard dev = 6.5)

• 0.1192

• 0.1251

• 0.1587

• 0.0875