Normal Distribution and Z Scores

Find the z-score for 258 given a mean of 273 and a standard deviation of 5.

• 3

• -2

• 2

• -3

Find the z-score for 62 given a mean of 30 and a standard deviation of 20.

• 1.6

• -1.6

• 11.6

• -11.6

Find the area under the standard normal curve that lies to the left of z=2.1.

• 1.79%

• -1.79%

• 98.21%

• 0.98%

Find the area under the standard normal curve that lies to the right of z=-0.67.

• 63.42%

• 74.86%

• 25.14%

• 50%

Find the area under the standard normal curve that lies between z=-0.5 and z=1.5.

• 62.46%

• 72.47%

• 5.40%

• 62.47%

What percentage of scores falls within 3 standard deviations of the mean?

• 68%

• 34%

• 99.7%

• 95%

Find the z-score with 20% of observations falling above it.

• z=-0.84

• z=1.84

• z=-1.84

• z=0.84

A 5th grader takes a test (mean=125, SD=15) and scores a 148. What is the child's percentile rank?

• 93%

• 68%

• 7%

• 99.7%

Mean=11, SD=30. Find the raw score (X) for z=-1.5

• 35

• 45

• 55

• 65

Test has a mean of 40 and a standard deviation of 10. What is the percent of people that scored above 62?

• 1.39%

• 45.34%

• 98.41%

• 22.34%