normalcdf & invNorm

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

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

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

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

At a high school, GPAs are normally distributed with a mean of 2.9 and standard deviation of 0.6. What GPA do you need to fall in the top 20%? The top 10%?

• 3.40 and 3.67

• 3.67 and 3.40

• 3.80 and 3.90

• 3.20 and 3.10

Tags

CCSS.HSS.ID.A.4

The mean life of a tire is 30,000 km. The standard deviation is 2000 km. The company will give you a refund for your tires if they fall in the lowest 5%. How many miles would get you a refund? What is the number of miles that would fall in the top 5%

• 26,700 km and 33,280 km

• 5,000 km and 25,000 km

Tags

CCSS.HSS.ID.A.4

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days. One company warns that because of the "freshness" of their ingredients, their products only have a shelf life of 5 days. What percentile is this? What percent of products have a longer shelf life?

• 1st percentile, 99%

• 99th percentile, 1%

Tags

CCSS.HSS.ID.A.4

Pat and Chris both took a spatial abilities test (mean = 80, standard deviation = 8). Pat scored a 76 and Chris scored a 94. Find z-scores for Pat and Chris. What percent of students scored higher than Pat? what percent of students scored lower than Chris? What score is needed to score in the top 25%?

• 69%, 96%, 85

• 85%, 69%, 96

• 96%, 69% 85

Tags

CCSS.HSS.ID.A.2

CCSS.HSS.ID.A.3

CCSS.HSS.ID.A.4