Stats ch 13
94. A researcher reports the following regression equation for two variables, X and Y: Y-hat = 5.10X -1.50 . If X = 2.30, then what is the value of Y-hat?
10.23
The standard error of estimate is used as a measure of the ______ in predictions using the equation of a regression line.
accuracy
A researcher computes a perfect negative correlation, in which each data point falls exactly on the regression line. In this example, the value of the standard error of estimate will be
equal to 0
The coefficient of determination is mathematically equivalent to
eta-squared
Which of the following indicates the strongest correlation
-.90
The correlation coefficient ranges between ______ and
-1, +1
A researcher measures the following correlation between number of years of education and life satisfaction: r = +.08. What is the value of the coefficient of determination
.01
A researcher measures the following correlation: r = -.21. What is the value of the coefficient of determination
.04
The correlation coefficient ranges from -1.0 to +1.0, with values closer to ±1.0 indicating
a stronger relationship between two factors
The following graphs display the data points for two linear correlations. Based on the information provided in these graphs, ______ displays a negative correlation and ______ displays a stronger correlation.
Graph B, Graph A
A researcher measures the following correlation between cost of produce and number of units sold. Which description best explains the relationship between these two factors
Less expensive produce is associated with an increased number of units sold
What is the problem with the following data for computing a correlation
The correlation coefficient will equal 0 because it violates the assumption of normality.
The more that the variability in ______ is associated with regression variation, the more likely it is that X predicts Y
Y
both sources of variation in an analysis of regression measure the variability in.
Y only
An unanticipated variable not accounted for in a research study that could be causing or associated with observed changes in one or more measured variables is called
a confound variable
The scores or data points for a regression analysis are typically reported in
a scatterplot
To summarize correlations, we report
all of the above
Linear regression describes the extent to which ______ predicts
all of these
Outliers can change the ______ of a correlation.
all of these
Select the description below that identifies the following correlation: r = .28, p < .01
all of these
The coefficient of determination is
all of these
The normality assumption states that the population of X and Y scores form a bivariate ("two variable") normal distribution, such that
all of these
Which of the following is a limitation for interpreting a correlation
all of these
Which of the following is used to determine the significance of predictions made by a best fitting linear equation
analysis of regression
The method of least squares is used to determine the ______ straight line to a set of data points.
best fitting
A statistical procedure used to describe the strength and direction of the linear relationship between two factors is called
correlation
The numerator of the correlation coefficient measures the extent to which two variables
covary
To summarize any type of regression analysis using APA format, we report each of the following except the
critical values
The phi correlation coefficient is a measure for the direction and strength of the linear relationship between two ______ variables
dichotomous
The assumption that there is an equal variance or scatter of data points dispersed along the regression line is referred to as
homoscedasticity
Which of the following is the assumption that there is an equal variance of data points dispersed along the regression line?
homoscedasticity
The regression equation measures
how far each data point deviates from the line that most closely fits the data
Which of the following is the assumption that the best way to describe the pattern of data is using a straight line
linearity
Which of the following is used to determine the linear equation that best fits a set of data points
method of least squares
Which of the following is not needed to compute the y-intercept using the method of least squares
mxy
The degrees of freedom associated with residual variation are equal to
n-2
A correlation coefficient can ______ demonstrate cause
never
The point-biserial correlation coefficient is a measure of the direction and strength of the linear relationship between two variables, where
one is continuous, and one is dichotomous
The Spearman rank-order correlation coefficient is a measure of the direction and strength of the linear relationship between two ______ variables
ordinal
A researcher measures the extent to which years of marriage predict perceptions of forgiveness. Which factor is the criterion variable in this example
perceptions of forgiveness
Using an analysis of regression, the variability in Y that is predicted by X is measured by the
regression variation
The correlation coefficient measures the extent to which changes in one factor are ______ in a second factor
related to changes
Using an analysis of regression, the variability in Y that is associated with error is measured by the
residual variation
A researcher observes a correlation of values from 2 to 10 points and draws conclusions about the full range of values in the population from 0 to 21 points. Which limitation for correctly interpreting a correlation coefficient did the researcher violate?
restriction of range
Which of the following is not needed to compute the slope using the method of least squares
ssy
An estimate of the standard deviation or distance that data points fall from the regression line is measured by the
standard error of estimate
The correlation coefficient is used to measure the ______ and ______ of the linear relationship between two factors
strength and direction
A researcher measures the extent to which time spent watching educational preschool television programming predicts success in school. Which factor is the criterion variable in this example
success in school
Which of the following statements is true regarding the sources of variation present in an analysis of regression
the closer the data points fall to the regression line, the more the variance in Y will be attributed to regression variation
The most common measure of effect size for the correlation coefficient is called
the coefficient of determination
Which of the following would not be reported for a correlation?
the critical values for each test
A researcher measures the following correlation between cups of coffee consumed daily and daily work schedule. Which description best explains the relationship between these two factors
the more a person works, the more coffee he or she tends to drink
The degrees of freedom associated with regression variation are equal to
the number of predictor variables
The appropriate correlation coefficient for measuring for the direction and strength of the linear relationship between two dichotomous variables is
the phi correlation coefficient
The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between one continuous and one dichotomous variable is
the point-biserial correlation coefficient
The appropriate correlation coefficient for measuring the direction and strength of the linear relationship between two ranked or ordinal variables is
the spearmen correlation coefficient
A researcher measures the extent to which the speed at which people eat (in minutes) predicts calorie intake (in kilocalories). Which factor is the predictor variable in this example
the speed at which people eat
What is the computation for the standard error of estimate
the square root of the mean square residual
The denominator of the correlation coefficient measures the extent to which two variables
vary independently