z-scores

Calculate the z score for a score of 90 if the mean is 75 and the standard deviation is 4.5.

• -3.33

• 3.33

• 1.77

• 2.1

Tags

CCSS.HSS.ID.A.4

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

• Adam scores 2.5 points higher than the average score

• He did better than EVERYONE.

• He scored 2.5 standard deviations above the average.

• Adam scored 2.5 points below the standard deviation

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

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

• Joanne scored 1.5 points below the mean

• She scored 1.5 standard deviations below the average.

• She did better than most people.

• Joanne's average score is 1.5 points below the mean.

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

• -1.25

• +1.25

• +1.20

• +1.02

Tags

CCSS.HSS.ID.A.4

Jill's Z-score on test with a class average of 82 and a standard deviation of 4 was a +3.0.

What was her actual score?

• 85 %

• 79 %

• 94 %

• 40 %

Tags

CCSS.HSS.ID.A.4

Tina got a 31 on the ACT, the mean was 23 and the SD was 4. Paula got 1400 on the SAT, the mean was 1100 and the SD was 500. Who performed better?

• Tina's performance is higher (more standard deviations above) from the mean so she did better.

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

• They both did the same.

• Paula's performance is higher (more standard deviations above) from the mean so she did better.

Tags

CCSS.HSS.ID.A.4

Women’s heights have a mean of 63.6 in. and a standard deviation of 2.5 inches.  The z score corresponding to a woman with a height is 2.56. How tall is the woman?

• 24.42 in
• 70 in
• 28in
• 68.6in

Tags

CCSS.HSS.ID.A.4

Yearling Angus steers had a mean weight of 1152 pounds with a standard deviation of 84 pounds. What's the actual weight of an animal whose z-score is - 1.5?

• 1026 pounds

• 1278 pounds

• 1020 pounds

• 1050 pounds

Tags

CCSS.HSS.ID.A.4

An incoming freshman took her college's placement exams in French and mathematics. In French, she scored 82 and in math 86. The overall results on the French exam had a mean of 72 and a standard deviation of 8, while the mean math score was 68, with a standard deviation of 12. On which exam did she do better compared with the other freshmen?

• French exam
• Math exam

Tags

CCSS.HSS.ID.A.2

CCSS.HSS.ID.A.3