Chapter 3: Measures of Central Tendency

Question 1

What is the mean of a data set?

Answer 1

• The average of a data set
• Also called the arithmetic mean
• Appropriate measure of central tendency for interval-level data

Question 2

What is the median of a data set?

Answer 2

• The middlemost value in a data set ordered from least to greatest
• The value that divides a distribution in two (half below and half above)
• Appropriate measure of central tendency for ordinal or interval-level data

Question 3

What is the mode of a data set?

Answer 3

• The number that occurs most often in a data set

- The only measure of central tendency appropriate for nominal-level variables

Question 4

What is a measure of central tendency?

Answer 4

A central or typical value for a frequency (probability) distribution, or data set

Question 5

What is the formula for calculating the mean of a data set?

Answer 5

mean = sum of raw scores/total # of scores in data set

Question 6

What is the formula for calculating the position of the median of a data set?

Answer 6

Position of median = N + 1 / 2

Question 7

What is the process for finding the median of a data set?

Answer 7

Step 1: Sort or order the distribution in ascending order (from lowest to highest)
Step 2: Find the position of the median using the formula: Position of median = N + 1 / 2
Step 3: locate the median

Question 8

When finding the median of a data set consisting of an odd number of values, what will be the result?

Answer 8

There will be a single middlemost value

Question 9

When finding the median of a data set consisting of an even number of values, what will be the result?

Answer 9

• There will be 2 middlemost values

- The halfway point between these 2 values should be used as the median

Question 10

What is a deviation?

Answer 10

• The distance and direction of any raw score from the mean
• The sum of the deviations that fall above the mean is equal in absolute value to the sum of the deviations that fall below the mean

Question 11

What is the formula for calculating the standard deviation of a population?

Answer 11

deviation = Square Root of the sum of (each raw score - the mean) squared / the # of values

Question 12

What is the formula for calculating the standard deviation for a sample group?

Answer 12

Standard deviation = The square root of the sum of (each value - the mean) squared / The total number of values - 1

Question 13

What is a population?

Answer 13

The total of all of the members of a group

Question 14

What is estimation theory?

Answer 14

A study that estimates the status of a population by using information gained from samples.

Question 15

What is descriptive statistics?

Answer 15

• A kind of statistics that seeks to describe the status of a group simply and clearly by organizing data.
• Regards the group as the population

Question 16

What is the weighted mean?

Answer 16

• The overall mean for a number of groups

- The “mean of the means”

Question 17

What is the formula for calculating the weighted mean?

Answer 17

weighted mean = The sum of the # of cases in the group x The mean of the group / The total # of cases combined

Question 18

3 most popular measures of central tendency

Answer 18

Mode, median, and mean