Normal Distributions

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

• 0.9236

• 0.1050

• 0.1600

• 0.0764

The mean temperature in Glens Falls for the month of February is 23 degrees with a standard deviation of 4.2 degrees. What is the probability that a randomly selected day will have a temperature of more than 17 degrees?

• 0.0062

• 0.0766

• 0.9234

• 0.9938

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 height of students is normally distributed with mean 145 and variance 25.
Find k if P(X $\le$  k)=0.9582

• 153.65

• 154.65

• 155.65

• 149.79

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

• 130.8

• 145.5

• 120

At Chili's, the average wait time to receive your meal is 22 minutes with a standard deviation of 9 minutes. What is the wait time for the top 12% ? Round to the nearest minute.

• 39 minutes

• 37 minutes

• 33 minutes

• 31 minutes

Rabbit's masses are normally distributed with a mean of 2.6kg and a variance of 1.44kg. A vet decides that the top 20% of rabbits are obese.

What is the minimum mass for an obese rabbit?

• 3.61kg

• 4.14kg

• 1.59kg

• 5.06kg

A bank's loan officer rates applicants for credit. The ratings can be described by a Normal model with a mean of 200 and a standard deviation of 50. What percentage ratings can be expected to be between 200 and 275?

• 43.31%

• 56.71%

• 38.61%

• 29.87%

Which is NOT true about the standard normal distribution?

• It is bell-shaped.

• It has a maximum.

• The mean is 0 and the standard deviation is 1.

• It is asymmetrical.