Normal Distribution (None empirical)

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%

What's the probability of x < 13 ?

(Mean = 20, Standard dev = 6.5)

• 0.1423

• 0.1401

• 0.0446

• 0.0359

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

(Mean = 50, Standard dev = 6.5)

• 0.1192

• 0.1251

• 0.1587

• 0.0875

The mean number of accidents a week at a company is 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

The mean number of accidents a week at a company is 6.4 with a standard deviation of 1.5.  What proportion of weeks would you expect to have less than 5 accidents?

• 0.6915
• 0.1762
• 0.8238
• -0.93

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%

The lengths of human pregnancies can be described by a Normal model with a mean of 268 days and a standard deviation of 15 days. What percentage of pregnancies will last at least 300 days?

• 1.64%

• 98.36%

• 12.34%

• 56.19%

For a recent English exam, the mean was 73 points and the standard deviation was 9.2 points. Find the percent of scores over 85.

• 9.61%

• 90.39%

• 28.51%

• 75.31%

A town has a speed limit of 45 mph. If the speeds of cars traveling in the town can be described by a Normal model with a mean of 48 mph and a standard deviation of 3.5 mph, what percent of cars are exceeding the speed limit?

• 80.43%

• 19.56%

• 23.86%

• 75%

A town's average snowfall is 48 inches per year with a standard deviation of 6 inches. Using a Normal model, what percent of snow fall amounts will be between 40 and 50?

• 53.93%

• 46.07%

• 37.19%

• 72.34%