Normal Probability Distribution

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 the gray area? (Mean = 55, Standard dev = 2.5)

• 0.8185

• 0.8413

• 0.8641

• 0.8389

What's the probability of 49 < x < 51 ? (Mean = 50, Standard dev = 6.5)

• 0.1192

• 0.1251

• 0.1587

• 0.0875

The 40 yards sprint times for a soccer team are found to be normally distributed with a mean of 5.2 seconds and a standard deviation of 0.3 seconds.  What is the z-score for a player who runs a time of 5.6 seconds?

• -1.33

• 1.33

• 0.0918

• 0.9082

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

Between what two standard deviations of a normal distribution contain 68% of the data?

• one below and one above

• two below and two above

• two below and zero

• zero and two above

According to the empirical rule, how much of the data falls within 3 standard deviations? 

• 25%

• 68%

• 95%

• 99.7%

What is the area under the curve between z = 0 and z = 1.45?

• .9265

• .4265

• .4500

• .5000

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