Module 5

Question 1

o Count, frequency, percent
o Shows how often something occurs
o Use this when you want to show how often a response is given

Answer 1

Measures of Frequency

Question 2

o Range, Variance, Standard Deviation
o Identifies the spread of scores (intervals)
o Use this when you want to show how “spread out” the data are
o It is helpful to know when your data are so spread out that it affects the mean

Answer 2

Measures of Dispersion or Variation

Question 3

o Mean, Median, and Mode
o Locates the distribution by various points
o Use this when you want to show how an average or most commonly indicated response

Answer 3

Measures of Central Tendency

Question 4

o Percentile Ranks, Quartile Ranks
o Describes how scores fall in relation to one another (standardized scores)
o Use this when you need to compare scores to a normalized score (e.g., a national norm)

Answer 4

Measures of Position

Question 5

 Statistical measure to determine a single score that defines the center of the distribution.
 Usually attempts to identify the “average” or “typical” individual
 Useful for making comparisons between groups of individuals or between sets of data

Answer 5

Measures of Central Tendency

Question 6

1. Easily understood - Not a distant mathematical abstraction
2. Objective and rigidly defined - Should encounter no question as to what the value is
3. Stable - Not affected materially by minor variations in the groups of items
4. Easily amenable to further statistical computation

Answer 6

Characteristics of a Good Average

Question 7

 Arithmetic average
 Computed by adding all the scores in the distribution and dividing by the number of scores

Answer 7

The Mean

Question 8

a modification of the usual mean that assigns weights (or measures of relative importance) to the observations to be averaged.

Answer 8

The Weighted Mean

Question 9

which of the statements are true or are they both true or false

i) The sum of the deviations of the values from the mean is zero.
ii) The sum of the squared deviations is minimum when the deviations are taken from the
mean

Answer 9

both statements are true

Question 10

 The positional middle of the arrayed data
 In an array, one-half of the values precede the _____and one-half follow it
 Definition and computations for a sample and for a population are the identical

Answer 10

The Median

Question 11

which of the statements are true or are the both true or false

1. The median is a positional measure.
2. The median is affected by the position of each item in the series but not by the value of each
   item. This means that extreme values affect the median less than the arithmetic mean.

Answer 11

both are true

Question 12

 The observed value that occurs most frequently
 Locates the point where the observation values occur with the greatest density

Answer 12

The Mode

Question 13

which of the statements about mode are true or are both true or false

1. It does not always exist; and if it does, it may not be unique. A Data Set is said to be unimodal if
   there is only one mode, bimodal if there are two modes, trimodal if there are three modes, and
   so on.
2. It is not affected by extreme values.
3. The mode can be used for qualitative as well as quantitative data.

Answer 13

both statements are true

Question 14

What is the correct measure of central tendency to use for the following?
 Extreme scores or skewed distributions
 Undetermined values
 Open-ended distributions
 Ordinal scales

Answer 14

Median

Question 15

What is the correct measure of central tendency to use for the following?
 Nominal scales
 Discrete variables
 Describing shape

Answer 15

Mode