Measures of Variation

Question 1

Measures of central location __ __ give an __ description of our data

Answer 1

do not give an adequate description of our data

Question 2

Most important statistics for measuring the variability of a set of data

Answer 2

• range
• variance

Question 3

the difference between the largest and smallest number in a set

Answer 3

range of a set of data

Question 4

provides a method for converting observed variances to standard form so that they can be more easily understood and compared

Answer 4

standard deviation

Question 5

provide the most powerful estimate of variation because they consider the value of each score

Answer 5

• standard deviation
• variance

Question 6

• least reliable of the measures and is used only when one is in a hurry to get a measure of variability
• may be used for ordinal, interval, or ratio data

Answer 6

range

Question 7

most important measures of variability

Answer 7

• standard deviation and its square,
• variance

Question 8

average of the squared deviation around the mean

Answer 8

variance

Question 9

• used whenever a distribution approximates a normal distribution
• basis for most statistics used in analysis of data

Answer 9

standard deviation

Question 10

range may be used for

Answer 10

• ordinal data
• interval data
• ratio data

Question 11

standard deviation is used with

Answer 11

• interval data
• ratio data

Question 12

a graph or data set organized to show the frequency of occurrence of each possible outcome of a repeatable event observed many times

Answer 12

frequency distribution

Question 13

data that are presented in the form of frequency distribution are called

Answer 13

grouped data

Question 14

lowest and largest values that can fall in a class interval

Answer 14

class limits

Question 15

number of observations falling in a particular class interval

Answer 15

class frequency

Question 16

numerical difference between the upper and lower class boundaries of a class interval

Answer 16

class width

Question 17

• midpoint of the class interval
• average of the class limits

Answer 17

class mark

Question 18

• total frequency of all values less than the upper class boundary of a given class interval
• used to determine the number of observations that lie above (or below) a particular value in a data set

Answer 18

Cumulative frequency

Question 19

plotting the class frequency against the class limits

Answer 19

bar chart

Question 20

frequency against the class boundaries

Answer 20

frequency histogram

Question 21

frequency against the class marks

Answer 21

frequency polygon

Question 22

cumulative frequency against the upper class boundaries

Answer 22

cumulative frequency polygon or ogive

Question 23

used when the median is used as an average; when the data depart noticeably from the normal

Answer 23

quartile deviation

Question 24

quartile deviation is used for what data

Answer 24

ordinal data

Question 25

quartile deviation Q is frequently called the

Answer 25

semi-interquartile range