Normal Distributions and Inverse Normal Distributions

In a survey of men in the United States (ages 20-29), the mean height was 69.6 inches with a standard deviation of 3.0 inches. Find the minimum height in the top 22%.

• 69.37 in 
• 67.58 in 
• 73.12 in 

Which is NOT true about the standard normal distribution?

• It is bell-shaped.
• It is unimodal.
• The mean is 0 and the standard deviation is 1.
• It is asymmetrical.

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%
• 34%
• 16%
• 2.5%

The distances male long jumpers for State College jump are approximately normal with a mean of 263 inches and a standard deviation of 14 inches.  
Suppose a male long jumper's jump ranked in the 75th percentile.  How long was his jump?

• 0.67 inch
• 263 inches
• 272.44 inches
• 277.25 inches

The scoring of modern IQ is such that Intelligence Quotients (IQs) have a normal distribution of μ= 100 and 𝞂 = 15.

Mensa International is a non-profit organization that accepts only people with IQ score within the top 2%. What level of IQ qualifies one to be a member of Mensa?

• 115
• 130.75
• 145
• 120

The average waist size for teenage males is 29 inches with a standard deviation of 1.4 inch. 
If waist sizes are normally distributed, estimate the proportion of teenagers who will have waist   sizes greater than 31 inches?

• 92.4%
• 10.5%
• 16%
• 7.6%

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%

Students pass a test if they score 50% or more.

The marks of a large number of students were sampled and the mean and standard deviation were calculated as 42% and 8% respectively.

Assuming this data is normally distributed, what percentage of students pass the test? in percentage...

• 5

• 16

• 24

• 32

68% of the marks in a test are between 51 and 64

Assuming this data is normally distributed, what are the mean and standard deviation?

• Mean = 57

  S.D. = 6.5

• Mean = 57

  S.D. = 7

• Mean = 57.5

  S.D. = 6.5

• Mean = 57.5

  S.D. = 13

The mean July daily rainfall in Hulu Kinta is 10 mm and the standard deviation is 1.5 mm

Assume that this data is normally distributed.

How many days in July would you expect the daily rainfall to be less than 8.5 mm?

• 5

• 6

• 7

• 10