Chapter 3- Central Tendency

Question 1

Central Tendency

Answer 1

Descriptive statistics that indicate a typical or representative score

They indicate a location for the bulk of a distribution’s scores

Question 2

Mean

Answer 2

X bar
The arithmetic average; the sum of the scores divided by the number of scores

Most commonly used and misused measure
An x bar is only one of many possible means from a population, because of this a degree of uncertainty comes with x bar
Mu carries no uncertainty

The mean is heavily influenced by extreme values
If skewed distribution use median instead of this

Cannot calculate mean for open-ended categories
Ex. 75 and over

Question 3

Deviation score

Answer 3

X- X bar

It must equal zero to check that you got the correct mean

Question 4

Median

Answer 4

The point that divides a distribution of scores into equal halves
Can be used for everything but nominal data
The median is not influenced by extreme values

Median location-

N+1 / 2

Question 5

Mode

Answer 5

Score that occurs most frequently in a distribution

Can be used for any scale of measurement
Possible to have multiple modes/no modes
Bimodal graphs have two modes

Mode is not influenced by value of scores, only influenced by frequency of scores

Question 6

Weighted Mean

Answer 6

Overall mean calculated from two or more samples with different

Question 7

Trimmed Mean

Answer 7

Excluding a certain number of values to prevent the mean from being skewed so much