2.5b Percentiles and Z-scores

If your doctor tells you that your height puts you in the 70th percentile, you will know that you are taller than __________ percent of people your age.

• 30

• 70

• 100

• 40

Tags

CCSS.7.RP.A.3

A student recently took the SATs and their score correlated to the 60th percentile. This means that ______________ percent of all students score at or higher than the score the student received.

• 60

• 40

• 20

• 100

Tags

CCSS.HSS.IC.B.4

CCSS.HSS.ID.A.4

The 50th percentile is also known as the _______________.

• median

• mean

• mode

• best percentile

Tags

CCSS.6.SP.A.2

CCSS.6.SP.A.3

CCSS.6.SP.B.5

The data below represents the scores students received on a recent Statistics quiz. Calculate the percentile for a student that scored 24 points.

15, 18, 19, 20, 21, 21, 22, 22, 24, 25

• 20th

• 80th

• 90th

• 99th

A positive z-score indicates that the given data value is _______________ the mean value of the data set.

• greater than

• less than

• equal to

Tags

CCSS.HSS.ID.A.4

A negative z-score indicates that the given data value is _______________ the mean value of the data set.

• greater than

• less than

• equal to

A z-score equal to zero indicates that the given data value is _______________.

• greater than the mean of the data set.

• less than the mean of the data set.

• equal to the mean of the data set.

• equal to zero.

Tags

CCSS.HSS.ID.A.4

What is the formula for calculating a z-score?

• $z=\frac{\mu-x}{\sigma}$

• $x=z\sigma+\mu$

• $\overline{x}=\frac{\Sigma x}{n}$

• $z=\frac{x-\mu}{\sigma}$

Tags

CCSS.HSS.ID.A.4

A recent Statistics quiz had a mean score of 20 points with a standard deviation of 3 points. If a student received a score of 21 points, what is their corresponding z-score? Please round to two decimal places.

• z = 0.33

• z = 14.33

• z = -0.33

• z = 0.90

Tags

CCSS.HSS.ID.A.4

A student's quiz score is two standard deviations below the class mean. What is the student's corresponding z-score for the quiz?

• z = 2

• z = 1

• z = -1

• z = -2

Tags

CCSS.HSS.ID.A.4