Summer Work

Question 1

Individuals

Answer 1

Individuals are the objects described by a set of data. Individuals may be people,
animals, or things.

Question 2

Variable

Answer 2

A variable is any characteristic of an individual. A variable can take different values
for different individuals.

Question 3

Categorical Variable

Answer 3

A categorical variable places an individual into one of several groups or categories.

Question 4

Quantitative Variable

Answer 4

A quantitative variable takes numerical values for which it makes sense to find an
average.

Question 5

Discrete Variables

Answer 5

If a variable can take on any value between its minimum value and its maximum value, it is called a continuous variable; otherwise, it is called a discrete variable.

Question 6

Univariate Data

Answer 6

When we conduct a study that looks at only one variable, we say that we are working with univariate data. Suppose, for example, that we conducted a survey to estimate the average weight of high school students. Since we are only working with one variable (weight), we would be working with univariate data.

Question 7

Bivariate Data

Answer 7

When we conduct a study that examines the relationship between two variables, we are working with bivariate data. Suppose we conducted a study to see if there were a relationship between the height and weight of high school students. Since we are working with two variables (height and weight), we would be working with bivariate data

Question 8

Population

Answer 8

the total set of observations that can be made.

Question 9

Sample

Answer 9

a set of observations drawn from a population.

Question 10

Census

Answer 10

A census is a study that obtains data from every member of a population.

Question 11

Distribution

Answer 11

The distribution of a variable tells us what values the variable takes and how often
it takes these values.

Question 12

Frequency Table

Answer 12

When a table shows frequency counts for a categorical variable, it is called a frequency table Below, the bar chart and the frequency table display the same data.

Question 13

Relative Frequency

Answer 13

A frequency count is a measure of the number of times that an event occurs. To compute relative frequency, one obtains a frequency count for the total population and a frequency count for a subgroup of the population. The relative frequency for the subgroup is

Question 14

Bar Graph

Answer 14

A bar chart is made up of columns or rows plotted on a graph. Here is how to read a bar chart made up of columns.

Question 15

Two-Way Table

Answer 15

A two-way table (also called a contingency table) is a useful tool for examining relationships between categorical variables. The entries in the cells of a two-way table can be frequency counts or relative frequencies

Question 16

Marginal Distribution

Answer 16

The marginal distribution of one of the categorical variables in a two-way table of
counts is the distribution of values of that variable among all individuals described by
the table.

Question 17

Conditional Distribution

Answer 17

A conditional distribution of a variable describes the values of that variable among individuals who have a specific value of another variable. There is a separate conditional distribution for each value of the other variable.

Question 18

Association

Answer 18

We say that there is an association between two variables if knowing the value of
one variable helps predict the value of the other.

Question 19

Dotplot

Answer 19

A dotplot is a type of graphic display used to compare frequency counts within categories or groups. As you might guess, a dotplot is made up of dots plotted on a graph.

Question 20

Mode

Answer 20

The mode is the most frequently appearing value in a population or sample.

Question 21

Range

Answer 21

The range is a simple measure of variation in a set of random variables. It is difference between the biggest and smallest random variable.

Question 22

Outlier

Answer 22

In regression analysis, a data point that diverges greatly from the overall pattern of data is called an outlier.

Question 23

Symmetric

Answer 23

Symmetry is an attribute used to describe the shape of a data distribution. When it is graphed, a symmetric distribution can be divided at the center so that each half is a mirror image of the other.

Question 24

Skewed Right

Answer 24

Distributions with fewer observations on the right (toward higher values) are said to be skewed right

Question 25

Skewed Left

Answer 25

Distributions with fewer observations on the left (toward lower values) are said to be skewed left.

Question 26

Unimodal

Answer 26

Distributions of data can have few or many peaks. Distributions with one clear peak are called unimodal

Question 27

Bimodal

Answer 27

Distributions with two clear peaks are called bimodal.

Question 28

Multimodal

Answer 28

Distributions with more than two clear peaks are called bimodal.

Question 29

Stemplot

Answer 29

A stemplot is used to display quantitative data, generally from small data sets (50 or fewer observations).

Question 30

Back-to-back Stem

Answer 30

Back-to-back stemplots are a graphic option for comparing data from two populations.

Question 31

Histogram

Answer 31

A histogram is made up of columns plotted on a graph. Here is how to read a histogram.

Question 32

Mean

Answer 32

A mean score is an average score, often denoted by X. It is the sum of individual scores divided by the number of individuals.

Question 33

Median

Answer 33

The median is a simple measure of central tendency. To find the median, we arrange the observations in order from smallest to largest value. If there is an odd number of observations, the median is the middle value. If there is an even number of observations, the median is the average of the two middle values.

Question 34

Interquartile Range

Answer 34

The interquartile range (IQR) is a measure of variability, based on dividing a data set into quartiles.

Question 35

Boxplot

Answer 35

A boxplot, sometimes called a box and whisker plot, is a type of graph used to display patterns of quantitative data.

Question 36

Standard Deviation

Answer 36

The standard deviation is a numerical value used to indicate how widely individuals in a group vary. If individual observations vary greatly from the group mean, the standard deviation is big; and vice versa.

Question 37

Variance

Answer 37

The variance is a numerical value used to indicate how widely individuals in a group vary. If individual observations vary greatly from the group mean, the variance is big; and vice versa.