Measures of Distribution Statistics

A national achievement test is administered annually to 3rd graders. The test has a mean score of 100 and a standard deviation of 15. If Jane's z-score is 1.20, what was her score on the test?

• 82

• 88

• 100

• 118

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.

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

So if Tina's Z-score is +2.0 and Paula's Z-score is +1.09, who performed better?

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

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

• They both did the same.

• Can I take a nap now?

What does a z-score of 0 mean?

• The score is equal to the mean.

• The score is 0 points. 

• There is no data.

• You can't tell unless you know the data is normal. 

What is the main problem associated with the mean value of some data?

• It is affected by the mode

• It is difficult to compute

• It is not a representative measure

• It is sensitive to outliers

What is the median?

• The middle value among some scores of a variable

• The average score or value

• The most frequent response or value for a variable

• The value between the minimum and maximum values of a variable

What is the mode?

• The value between the minimum and maximum values of a variable

• The average score or value

• The middle value among some scores of a variable

• The most frequent response or value for a variable

What does the range measure?

• The difference between the minimum and maximum values of a variable

• The standard deviation squared

• The distance between the mean and median

• The spread or range of variability

What is the interquartile range in a data set?

• The range between the first quartile and the third quartile

• The range between the minimum and maximum values

• The range between the mean and the median

• The range between the mode and the median