Empirical Rule

Which interval shows 95% of the data given a mean of 15 and a standard deviation of 3? 

• 9 to 21
• 12 to 18
• 6 to 24
• 13 to 16

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?

• 5
• 16
• 24
• 32

Tags

CCSS.HSF-LE.A.1B

At a local high school, GPA's are normally distributed with a mean of 2.9 and standard deviation of 0.6. What is the GPA of the highest 2.5% of the students?

• 4.1 
• 4.1 or higher
• 4.7
• 4.5 or higher

Tags

CCSS.HSF-LE.A.1B

What percent of people within 2 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

What percent of people within 3 standard deviations of the mean?

• 99.7

• 34

• 68

• 95

What percent of people within 1 standard deviation of the mean?

• 99.7

• 34

• 68

• 95

The normal curve is symmetrical about the mean.

• True
• False

If heights of 3rd graders follow a normal distribution with a mean of 52 inches and a standard deviation of 2.5 inches, what is the z score of a 3rd grader who is 47 inches tall? 

• -5
• -2
• 2
• 5

Given a mean of 75 and a standard deviation of 7, how many students out of 500 would score higher than 82?

• 475

• 170

• 237

• 80

A z-score tells you...

• the standard deviation of a sampling distribution.
• the original raw score on which it is based.
• if the distribution it comes from is normal.
• how many standard deviations away from the mean a score lies.