Measures of Center and Measures of Spread

What conclusion can Ms. Long make about the performance of her first- and second-period classes?

• The first-period class had a higher median score than the second-period class.

• The second-period class scores had a higher mean than the first-period class scores.

• The first-period class scores had a greater range than the second-period class scores.

• The second-period class scores had a greater mean absolute deviation than the first-period class scores.

What is the median of the data?

• 200

• 100

• 90

• 140

calculate the median for the following set of scores 45, 69, 69, 87, 88, 92, 99, 100

• 87

• 55

• 87.5

• 99

Which mean absolute deviation would have a greater variability or spread?  4.2 or 8.5?

• 4.2

• 8.5

• neither

• they are equal

Which summary statistic should be used to compare the two data sets and why?

• The median and the interquartile range because they are normally distributed.

• The median and the interquartile range because they are skewed.

• The mean and the standard deviation because they are normally distributed.

• The mean and the standard deviation because they are skewed.

Which statistic measures how spread out the data values are in a data set?

• mean

• mode

• maximum value

• standard deviation

A class scored 83,83,87,87,88,88,91,94,95,96,98,100,100 on a test, but then a student scored a 28.

The mean will ​ (a)  

The median will ​ (b)  

The ​ (c)   is the best measure of center for this data.

• decrease

• increase

• stay the same

• go up

• go down

• median

• mean

Which of the following is a measure of spread, or variability?

(select all that apply)

• Interquartile Range

• Standard Deviation

• Mean

• Median

• Range

Which dot plot shows more variability? a or b?

• a

• b

• they are equal

Find the MEDIAN
77, 83, 83, 85, 87, 90, 90, 93, 94, 99, 99

• 77

• 99

• 90

• 87