Finding z-scores

What is the correct formula for finding z-scores?

• $z=\frac{x-\mu}{\sigma}$

• $z=\frac{\mu-x}{\sigma}$

• $S_x=\frac{x-\mu}{\sigma}$

Tags

CCSS.HSS.ID.A.4

Composite scores on the ACT are normally distributed with a mean of 21 and standard deviation of 5. Find the z-score for a student that gets a 31.

• -2.00

• 2.00

• 1.50

• 0.00

Tags

CCSS.HSS.ID.A.4

Heights of students at PV are normally distributed with

 $\mu=65in$  and  $\sigma=3in$ 
Find the z-score for a student that is 62 inches tall. 

• z = -1.00

• z = 1.00in

• z = 2.00

• z = -1.00in

Tags

CCSS.HSS.ID.A.4

A student scores a 75% on her chemistry test with a z-score of 2.34, and an 87% on her English test with a z-score of 1.52.

In which class did she perform better in, relative to her peers?

• English

• She did about equally well on both

• Chemistry

• Impossible to tell

Tags

CCSS.HSS.ID.A.2

CCSS.HSS.ID.A.3

Weights of wallabies are normally distributed with a mean of 9lbs and a standard deviation of 1.5lbs. Which weight would correspond to a z-score of -2?

• 9lbs

• 10.5lbs

• 7.5lbs

• 6lbs

• 12lbs

Tags

CCSS.HSS.ID.A.4

Which of the following are true statements regarding z-scores?

• They include units

• They do not include units

• A negative z-score suggests the observation is less than the mean

• They are calculated using Medians and IQR's

• They are calculated using Means and Standard Deviations

Tags

CCSS.HSS.ID.A.4

Composite scores on the ACT are normally distributed with a mean of 21 and standard deviation of 5.

Find the z-score for a student that scores a 28.

Tags

CCSS.HSS.ID.A.4

Home prices in a certain neighborhood are normally distributed with a mean of $200,000 and a standard deviation of $10,000. Which of the following is the z-score for a home that costs $193,000?

• -$0.70

• $0.70

• -0.70

• 0.70

Tags

CCSS.HSS.ID.A.4