CH13 Univariate and Bivariate Analysis of Quantitative Data

Question 1

the set of different values of a variable that have been observed and how common each value is

Answer 1

distributions

Question 2

a distribution of the possible values of a variable along with the number of observations for each value that was observed

Answer 2

frequency distribution

Question 3

a presentation of the possible values of a variable along with the percentage of observations for each value that was observed

Answer 3

relative distribution

Question 4

ideal visual presentation for categorical variable

Answer 4

bar graph

Question 5

visualization for the frequency distribution of a continuous variable, with bars representing a range of values of a continuous variable

Answer 5

histogram

Question 6

a single value that summarizes some feature of a distribution

Answer 6

summary statistic

Question 7

Summary statistics that indicate the middle of a distribution

Answer 7

measures of central tendency

Question 8

the sum of all of a variable’s values divided by the number of observations

Use:
1) at ? level (unless skewed)
2) to report ? score (the fulcrum that exactly balances all scores)
3) to anticipate additional statistical analysis

Answer 8

mean

1) interval/ratio
2) typical

Question 9

the middle value observed when observations are ranked from the lowest to the highest (useful bc it disregards outliers)

Use:
1) at ? level
2) when ? level has skewed distribution
3) to report ? (always lies at exact center of distribution)

Answer 9

median

1) ordinal
2) interval/ratio
3) central score

Question 10

the most common value of a variable, is the closest measure to “average” for a nominal variable

Use:
1) at ? level
2) for quick and easy measure for ? variables
3) to report most ? score

Answer 10

mode

1) nominal
2) ordinal/interval/ratio
3) most common score

Question 11

describes the amount by which each observation in a distribution varies, or differs, from the others

Answer 11

variation

Question 12

3 measures of variation for quantitative variables

Answer 12

Range, the interquartile range, and the standard deviation

Question 13

The simplest variation; the difference between the maximum and minimum values of a distribution

Answer 13

range (R)

Question 14

the difference between the first quartile and the third quartile (only use middle two quartiles); avoids the problem created by outliers, by showing the range where most cases lie.

Answer 14

interquartile range

Question 15

the points in a distribution corresponding to the first 25% of the cases, the first 50% of the cases, and the first 75% of the cases.

Answer 15

quartile (Q)

Question 16

the average distance between the value of each observation and the overall mean; formally the square root of the average squared differences between the values of a distribution and the distribution’s mean

Answer 16

standard deviation (s)

Question 17

When a variable is normally distributed, 68% of the cases (almost exactly 2/3) will lie between plus and minus 1 standard deviation from the distribution’s mean, and 95% of the cases will lie between plus and minus 2 standard deviations from the mean, 99% of cases are plus and minus 3 standard deviation from mean; always symmetric

Answer 17

normal distribution

Question 18

General relationship in normal distribution

standard deviation percentages

Answer 18

+- 1s = about 69%
+- 2s = about 95%
+- 3s = about 99%

Question 19

Fundamental aspects of a normal curve

Answer 19

Bell Shaped
Unimodal
Symmetrical
Unskewed
Theoretical
Mode, Median, and Mean are equal

Question 20

a presentation of distributions between two or more variables as a table. The table presents the categories of one variable as rows and the categories of the other variable as columns

Answer 20

cross tabulation

Question 21

The totals in the bottom row and right-most column

Answer 21

marginal frequencies