BYU STAT 121 Exam Questions Verified Answers Latest
Update 2025
correlation coefficient - ANS a measure of the strength of the linear relationship between 2
variables
bivariate quantitative data - ANS the type of data required for a regression analysis
response variable - ANS a variable that gives the value (may not be a number) of the outcome
of a study on each individual
What are the 2 requirements for computing a correlation coefficient? - ANS 1. the two variables
must be quantitative
2. their relationship must be linear
What is a scatterplot? - ANS a 2-dimensional plot used to examine strength of a relationship
between 2 variables as well as direction and type of relationship
Outlier - ANS an observation that substantially alters the correlation coefficient value (1.5 x Q3-
Q2)
Positive association - ANS Type of association where the high values of one variable tend to
associate with high values of another variable.
The max and min possible values of correlation coefficient - ANS +1 & -1
the unit of measure for the correlation coefficient - ANS there is no unit of measure
the value of the correlation coefficient when there is no linear association between two
quantitative variables - ANS 0
, a graph for displaying bivariate quantitative data - ANS a scatterplot
the symbol for sample correlation coefficient - ANS " r "
lower case
a measure of the strength of the linear relationship between x and y - ANS correlation
coefficient
the line with the smallest sum of squared residuals - ANS least squares regression line
a plot of the residuals versus the observed x values - ANS residual plot
requirements for computing correlation coefficient - ANS bivariate quantitative data with a
linear relationship
The name of the value computed from observed y minus predicted y - ANS residual
residual plot - ANS a diagnostic tool used to determine if a regression model is a good fit
the pattern in a residual plot indicating lack of linearity - ANS a smile or frown
the pattern in a residual plot indicating that the variability of the y's is not constant across all x
values - ANS a megaphone
a measure of the percentage of variation in Y explained by X - ANS r^2
a measure of the average change in Y for every one unit increase in X - ANS slope
Update 2025
correlation coefficient - ANS a measure of the strength of the linear relationship between 2
variables
bivariate quantitative data - ANS the type of data required for a regression analysis
response variable - ANS a variable that gives the value (may not be a number) of the outcome
of a study on each individual
What are the 2 requirements for computing a correlation coefficient? - ANS 1. the two variables
must be quantitative
2. their relationship must be linear
What is a scatterplot? - ANS a 2-dimensional plot used to examine strength of a relationship
between 2 variables as well as direction and type of relationship
Outlier - ANS an observation that substantially alters the correlation coefficient value (1.5 x Q3-
Q2)
Positive association - ANS Type of association where the high values of one variable tend to
associate with high values of another variable.
The max and min possible values of correlation coefficient - ANS +1 & -1
the unit of measure for the correlation coefficient - ANS there is no unit of measure
the value of the correlation coefficient when there is no linear association between two
quantitative variables - ANS 0
, a graph for displaying bivariate quantitative data - ANS a scatterplot
the symbol for sample correlation coefficient - ANS " r "
lower case
a measure of the strength of the linear relationship between x and y - ANS correlation
coefficient
the line with the smallest sum of squared residuals - ANS least squares regression line
a plot of the residuals versus the observed x values - ANS residual plot
requirements for computing correlation coefficient - ANS bivariate quantitative data with a
linear relationship
The name of the value computed from observed y minus predicted y - ANS residual
residual plot - ANS a diagnostic tool used to determine if a regression model is a good fit
the pattern in a residual plot indicating lack of linearity - ANS a smile or frown
the pattern in a residual plot indicating that the variability of the y's is not constant across all x
values - ANS a megaphone
a measure of the percentage of variation in Y explained by X - ANS r^2
a measure of the average change in Y for every one unit increase in X - ANS slope
