Percentiles

At a local high school, GPAs are normally distributed with a mean of 2.9 and standard deviation of 0.6. What is the z-score for the 80th percentile? What GPA falls at the 80th percentile?

• z= -0.84, A GPA of 3.40

• z= -0,84, A GPA of 0.8

• z= 0.84, A GPA of 3.80

• z= 0.84, A GPA of 3.40

Tags

CCSS.HSS.ID.A.4

A 12 oz. can of soda has a mean volume of 12 oz, with a standard deviation of 0.25 oz. Find the z-score for the 90th percentile. How many ounces would the can have to fall at the 90th percentile?

• z= 1.28, 13 ounces and above

• z= 1.28, 12.32 ounces and above

• z= 1.28. 0.9 ounces and above

• z= -1/28, 12.32 ounces

Tags

CCSS.HSS.ID.A.4

Scored on a certain standardized test have a mean of 500, and a standard deviation of 100. What is the z-score for a value of 410? What is the percentile?

• z= 0.9, 82nd percentile

• z= -0.9, 82nd percentile

• z= -0.9, 18th percentile

• z= 0.9, 18th percentile

Tags

CCSS.HSS.ID.A.4

In a factory, the weight of the concrete poured into a mold by a machine follows a normal distribution with a mean of 1150 pounds and a standard deviation of 22 pounds. What is the z-score for 1200 pounds? What percentile is this?

• z=2.27, 99th percentile

• z-=2.27, 1st percentile

• z=-2.27, 1st percentile

• z=-2.27, 99th percentile

Tags

CCSS.HSS.ID.A.4

What is the z-score value that corresponds to the 30th percentile?

• -1.02
• -.52
• .52
• 1.02

Tags

CCSS.HSS.ID.A.4

The percentile represents the....

• percent of data values that are below.
• percent of data values that are above.
• number of data values that are below.
• number of data values that are below.

If I tell you that you scored at the 55th percentile on your final exam, you would know:

• 55% of the class scored as good or worse than I did 
• I earned a 55% on the exam
• I failed the exam
• 45% of the class scored worse than I did 

Tags

CCSS.6.SP.A.2

CCSS.6.SP.B.5

The shelf life of a particular dairy product is normally distributed with a mean is 12 days and a standard deviation of 3 days. Find the z-score of a dairy product that has a shelf life of 14 days. What percentile is this?

• z=0.33, 50th percentile

• z=0.66, 75th percentile

• z=0.66., 84th percentile

Tags

CCSS.HSS.ID.A.4

At a high school, GPAs are normally distributed with a mean of 2.9 and a standard deviation of 0.6. Find the z-score of a GPA of 3.2? What percentile is this?

• z=0.5, 67th percentile

• z=0.5, 69th percentile

Tags

CCSS.HSS.ID.A.4

The mean life of a tire is 30,000 km. The standard deviation is 2000 km. What is the z-score of a tire that lasts 27, 500 miles. What percentile is this?

• z=-1.25, 9th percentile

• z=-1.25, 11th percentile

Tags

CCSS.HSS.ID.A.4