Module 5: descriptive statistics for two variables

Question 1

joint frequencies

Answer 1

The frequency counts in each cell of the table.

Question 2

marginal frequencies

Answer 2

The totals of each row and column in a table; given this name because they are in the ‘margins’ of the table.

Question 3

response variable

Answer 3

The variable that is obtained as a result, or the response that gets measured or observed. Also called a Dependent variable.

Question 4

cluster

Answer 4

Several points are grouped together away from the majority of points in a data set.

Question 5

positive correlation

Answer 5

When two quantitative variables move in the same direction; the response variable increases when the explanatory variable increases.

Question 6

contingency table

Answer 6

A table that contains frequency counts for two categorical variables. [See also two-way frequency table]

Question 7

explanatory variable

Answer 7

The variable that may be the cause of some result, or is presented as variable that offers an explanation. Also called an Independent variable.

Question 8

ordered pair

Answer 8

Two numbers written in the form (x,y), where x represents the x-value or x-coordinate, and y represents the y-value or y-coordinate.

Question 9

non-linear

Answer 9

An expression or equation that is illustrated by something other than a straight line.

Question 10

linear

Answer 10

An expression or equation of degree 1.

Question 11

independent variable

Answer 11

The variable that may be the cause of some result, or is presented as variable that offers an explanation. Also called an explanatory variable.

Question 12

scatterplot

Answer 12

A graph that uses dots on a coordinate plane to show the relationship between two quantitative variables.

Question 13

box plot

Answer 13

A graphical rendering of the range and the first and third quartiles of a data set with the data set’s median in the center.

Question 14

no correlation

Answer 14

There is no apparent overall trend between the two variables. If the correlation coefficient is 0, this only rules out a linear trend. There could be a non-linear or curvilinear trend.

Question 15

relative frequency

Answer 15

A way to approximate a percentage by dividing the number of times an event occurred in an experiment by the total number of trials.

Question 16

dependent variable

Answer 16

The variable that is obtained as a result, or is the response that gets measured or observed. Also called a response variable.

Question 17

outlier

Answer 17

An observation point that is significantly distant from the other observations in the dataset.

Question 18

five-number summary

Answer 18

The minimum, first quartile, median, third quartile, and the maximum. A box plot represents the five numbers in a five-number summary.

Question 19

negative correlation

Answer 19

When two quantitative variables move in opposite directions: as the explanatory variable increases the response variable decreases.

Question 20

conditional percentages

Answer 20

A way to approximate a percentage by dividing the number of times an event occurred in an experiment by the total number of respondents in that row or column. See relative frequency.

Question 21

two-way frequency table

Answer 21

A table that contains frequency counts for two categorical variables. [See also contingency table]

Question 22

coordinate plane

Answer 22

A tool used for graphing that is a display of a two-dimensional plane. It consists of an x-axis and a y-axis; the x-axis being a horizontal number line, the y-axis is a vertical number line, and the axes meet at the origin (0, 0).

Question 23

correlation

Answer 23

An observed relationship between two quantitative variables. While this is most commonly a linear relationship, it does not need to be.