Ch. 3

Question 1

A value used to describe the central tendency of a set of data

Answer 1

Measure of location

Question 2

What are some common measures of location

Answer 2

Arithmetic Mean, weighted mean, geometric mean, Median, and Mode

Question 3

How big the variation or spread in data is

Answer 3

Dispersion

Question 4

The most widely used and widely reported measure of location. Used as both population parameter and sample statistic

Answer 4

Arithmetic Mean

Question 5

The sum of all values in a population divided by the number of values in the population.

Answer 5

Populations Mean

Question 6

A characteristic of a population

Answer 6

Parameter

Question 7

The sum of all the sampled values divided by the total number of sampled values.

Answer 7

Sample Mean

Question 8

A characteristic of a sample

Answer 8

Statistic

Question 9

The midpoint or center value after they have been ordered from the minimum to the maximum values

Answer 9

Median

Question 10

For the median, what is the minimal level of measurement

Answer 10

Ordinal

Question 11

What are major properties of the median

Answer 11

1. It is not affected by extremely large or small values
2. It can be computed at ordinal-level data or higher

Question 12

The value of observations that appears most frequently

Answer 12

Mode

Question 13

What’s the advantage of the mode

Answer 13

Extremely high or low values don’t affect its value

Question 14

What are disadvantages of the mode

Answer 14

1. There may not be a mode in some data sets
2. There may be multiple modes (bimodal or multi-modal)

Question 15

A value that shows the spread of a data set. The range, variance, and standard deviation are examples

Answer 15

Measures of dispersion

Question 16

A convenient way to compute the arithmetic mean when there are several observations of the same value

Answer 16

The weighted mean

Question 17

A set of n positive numbers computed as the nth root of the product of n values. Useful for finding average rates of change

Answer 17

The geometric mean

Question 18

What is the formula for geometric mean for rate of increase over time

Answer 18

nth root for number of years of ending value divided by beginning value, then subtracting one from the answer.

Question 19

The maximum - minimum values in a data set

Answer 19

The range

Question 20

What is a limitation of the range

Answer 20

It only accounts for two values

Question 21

The arithmetic mean of the squared deviations from the mean

Answer 21

The Variance

Question 22

How do you calculate the variance

Answer 22

square the difference of the value - mean, divide the sum of the differences by the number of values

Question 23

The square root of the population variance

Answer 23

Standard deviation

Question 24

What’s the difference in formulas from population variance to sample variance

Answer 24

Denominator in population variance is n, in the sample variance, it’s n-1

Question 25

For any set of observations, the proportion of the values that lie within k standard deviations of the mean is at least 1-1/k squared, where k is any value greater than 1.

Answer 25

Chebyshev’s Theorem

Question 26

What is the empirical rule for symmetrical bell shaped frequency distribution

Answer 26

About 68% with be with +-1 standard deviations
About 95 percent will be with +-2 standard deviations
and about 99.7% will be within plus or minus 3 standard deviations