10.3-10.4 Practice

What is the Z-score for Tina if she got a 31 on the ACT, the mean was 23 and the SD was 4?

• +0.20

• +2.00

• -2.00

• -0.20

Tags

CCSS.HSS.ID.A.4

So if Tina's Z-score is +2.00 and Paula's Z-score is +1.09, who performed better?

• Tina's performance is farther above the mean so she did better.

• Paula's score is closer to the mean so she did better.

• They both did the same.

Tags

CCSS.HSS.ID.A.2

CCSS.HSS.ID.A.3

CCSS.HSS.ID.A.4

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 normal distribution, what percent of the values lie above the mean?

• 13.5%

• 34%

• 50%

• 68%

Tags

CCSS.HSS.ID.A.4

In a normal distribution, what percent of the values lie within one standard deviation of the mean?

(from z = -1 to z = 1)

• 13.5%

• 34%

• 95%

• 68%

Tags

CCSS.HSS.ID.A.4

2000 freshmen at State Univ. took a Biology test. The scores were distributed normally with μ=70 and σ=5.

What percent of scores are between 65 and 75?

• 34%

• 50%

• 68%

• 81.5%

Tags

CCSS.HSS.ID.A.4

2000 freshmen at State Univ. took a Biology test. The scores were distributed normally with μ=70 and σ=5.

What percent of scores are greater than 75?

• 2.35%

• 2.5%

• 16%

• 13.5%

Tags

CCSS.HSS.ID.A.4

500 juniors at Central High School took the ACT last year. The scores were distributed normally with μ=24 and σ=4.

What ACT score is 3 standard deviations below the mean?

• 12

• 16

• 20

• 21

Tags

CCSS.HSS.ID.A.4

According to the empirical rule, how much of the data falls within 3 standard deviations? 

• 25%
• 68%
• 95%
• 99.7%

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

CCSS.HSS.MD.A.3