z-score practice

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

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. Approximately 95% of molds filled by this machine will hold weights in what interval? 

• 1084 to 1216 pounds 
• 1106 to 1150 pounds 
• 1106 to 1194 pounds 
• 1128 to 1172 pounds

Tags

CCSS.HSS.ID.A.4

A national achievement test is administered annually to 3rd graders. The test has a mean score of 100 and a standard deviation of 15. If Jane's z-score is 1.20, what was her score on the test?

• 82
• 88
• 100
• 118

Tags

CCSS.HSA.REI.B.3

CCSS.HSS.ID.A.4

The mean life of a tire is 30,000 km. The standard deviation is 2000 km.

Then, 68% of all tires will have a life between ___________ km and __________ km.

•  28,000 km and 32,000 km.
• 24,000 km and 34,000 km.
• 26,000 km and 34,000 km.
• 27,000 km and 31,000 km.

Tags

CCSS.HSS.ID.A.4

The average waist size for teenage males is 29 inches with a standard deviation of 2 inches. 
If waist sizes are normally distributed, determine the z-score of a teenage male with a 33 inch waist.  

• 2
• 1
• -2
• -1

Tags

CCSS.HSS.ID.A.4

The mean temperature in Glens Falls for the month of February is 23 degrees with a standard deviation of 4.2 degrees.  What is the z-score for a temperature of 17 degrees?  

• 1 
• 1.43
• -1.43
• 11.5

Tags

CCSS.HSS.ID.A.4

The mean temperature in Glens Falls for the month of February is 23 degrees with a standard deviation of 4.2 degrees.  Approximately what percent of days in February will have days below 23 degrees?

• 5%
• 34%
• 50%
• 68%

Tags

CCSS.HSS.ID.A.4

The number of miles that Jenna cycled each week for a 7-week period is shown: 
36, 42, 28, 52, 48, 36, 31 
What is the median number of miles Jenna cycled?

• 24
• 36
• 39
• 52

Tags

CCSS.HSS.ID.A.2

The number of pages that Carolyn wrote in her journal each day from Monday to Friday is shown below: 
9, 8, 12, 6, 10
What is the mean number of pages she wrote per day?

• 5
• 6
• 9
• 11

Tags

CCSS.HSS.ID.A.2

The normal curve is symmetrical about the mean.

• True
• False