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