Z Score Review

Adam's Z-score on a test is +2.5.  What does this mean?

• He'd better start studying.
• He did better than EVERYONE.
• He scored 2.5 standard deviations above the average.
• He did terrible.

Tags

CCSS.HSS.ID.A.4

Joanne's Z-score is -1.5.  What does this mean?

• She didn't take the test yet.
• She scored 1.5 standard deviations below the average.
• She did better than most people.
• No clue

Tags

CCSS.HSS.ID.A.4

Which of the following is a formula that describes calculating a z-score?

• Z = (score - mean) / stand. devation

• Z = (mean - score) / stand. dev.

• Z = score/stand. dev/ mean

• Z = dragonball

Tags

CCSS.HSS.ID.A.4

If Gonzalo's score is 87, the class average is 82, and the SD is 4, what is Gonzalo's Z-score?

• -1.25
• +1.25
• +1.20
• +1.02

Tags

CCSS.HSS.ID.A.4

Find the Z-score.

Mean = 22

Standard Deviation: 3.1

x = 29

• 2.26

• 16.45

• -2.26

• 1.26

Tags

CCSS.HSS.ID.A.4

μ = 10 , σ = 5 , X = 12 . Find z-score

• 0.3
• 0.4
• 0.5
• 0.6

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

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 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

Aaron scored a 68% on his Biology test, where the class average was a 75% with a standard deviation of 3.3%. On his History test, Aaron scored a 78% but was disappointed in his score because the class average was a 93% with a standard deviation of 5.7%. Which test did Aaron score more poorly on and why? Select all that apply.

• Aaron's Biology test is worse relative to his classmates

• Aaron's History test is worse relative to his classmates

• Because he scored 2.63 standard deviations below the mean compared to 2.12 below the mean on the other test.

• Because he scored 2.12 standard deviations below the mean compared to 2.63 below the mean on the other test.