Module 5: descriptive statistics for two variables Flashcards
joint frequencies
The frequency counts in each cell of the table.
marginal frequencies
The totals of each row and column in a table; given this name because they are in the ‘margins’ of the table.
response variable
The variable that is obtained as a result, or the response that gets measured or observed. Also called a Dependent variable.
cluster
Several points are grouped together away from the majority of points in a data set.
positive correlation
When two quantitative variables move in the same direction; the response variable increases when the explanatory variable increases.
contingency table
A table that contains frequency counts for two categorical variables. [See also two-way frequency table]
explanatory variable
The variable that may be the cause of some result, or is presented as variable that offers an explanation. Also called an Independent variable.
ordered pair
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.
non-linear
An expression or equation that is illustrated by something other than a straight line.
linear
An expression or equation of degree 1.
independent variable
The variable that may be the cause of some result, or is presented as variable that offers an explanation. Also called an explanatory variable.
scatterplot
A graph that uses dots on a coordinate plane to show the relationship between two quantitative variables.
box plot
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.
no correlation
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.
relative frequency
A way to approximate a percentage by dividing the number of times an event occurred in an experiment by the total number of trials.
dependent variable
The variable that is obtained as a result, or is the response that gets measured or observed. Also called a response variable.
outlier
An observation point that is significantly distant from the other observations in the dataset.
five-number summary
The minimum, first quartile, median, third quartile, and the maximum. A box plot represents the five numbers in a five-number summary.
negative correlation
When two quantitative variables move in opposite directions: as the explanatory variable increases the response variable decreases.
conditional percentages
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.
two-way frequency table
A table that contains frequency counts for two categorical variables. [See also contingency table]
coordinate plane
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).
correlation
An observed relationship between two quantitative variables. While this is most commonly a linear relationship, it does not need to be.
