Measures of Dispersion

Question 1

A set of data equal to the largest measurement (maximum) minus the smallest measurement (minimum).

Answer 1

Range

Question 2

The _________ of a population is the average of the squared deviations from the mean of each data point.

Answer 2

Variance

Question 3

The positive square root of the variance, thought of as a typical distance from the mean is known as?

Answer 3

Standard Deviation

Question 4

R = Xmax - Xmin is the formula for _________.

Answer 4

range

Question 5

The disadvantage of range is that by using only the two furthest separated data points, the ________ of the remaining data points around the mean is ignored.

Answer 5

dispersion

Question 6

T or F

No matter the shape of data, at least 75% falls within 2 std dev and almost 90% (89.9) is within 3 std dev.

Answer 6

T

Question 7

T or F

If a constant is added to each value in a data set to produce a new data set, the std dev of the new data set will be larger.

Answer 7

F - Will remain equal to the std dev of the original data set

Question 8

The sum of the deviations of the scores about the mean for any data set is always _______.

Answer 8

zero

Question 9

If a constant is added to each data point in a sample, the measures of dispersion will remain unchanged. What measure of central tendency will adjust?

Answer 9

Mean

Question 10

For bell shaped curves, ______ of the data can be expected to be within a std dev of two.

Answer 10

95%

Question 11

_______ _______, such as X-bar and R charts, show upper and lower control limits and when a variation exceeds those controls.

Answer 11

Control Charts

Question 12

Variation is either _______ or _______, meaning it was predictable or a one-off.

Answer 12

assignable / chance