Stats chapter 13
A sales manager for an advertising agency believes that there is a relationship between the number of contacts that a salesperson makes and the amount of sales dollars earned. A regression ANOVA shows the following results: Picture What is the value of the coefficient of correlation?
+0.9754
A sales manager for an advertising agency believes that there is a relationship between the number of contacts that a salesperson makes and the amount of sales dollars earned. A regression analysis shows the following results: Picture What is the Y-intercept of the linear equation?
-12.201
If r = 0.65, what does the coefficient of determination equal?
0.4225
Consider the following regression equation: Y = 30 + 8X. If SSE = 720 and SS Total = 1,200, then the correlation coefficient is _______.
0.632
A sales manager for an advertising agency believes that there is a relationship between the number of contacts that a salesperson makes and the amount of sales dollars earned. A regression ANOVA shows the following results: Picture What is the value of the coefficient of determination?
0.9513
Using the following information: Picture What is the correlation coefficient?
0.9583
A hypothesis test is conducted at the .05 level of significance to test whether or not the population correlation is zero. If the sample consists of 25 observations and the correlation coefficient is 0.60, what is the computed value of the test statistic? Round to two decimal places.
3.60
A regression analysis yields the following information: Ŷ= 2.21+1.49x ; n = 10; s(subscript)y∙x = 1.66; ΣX = 32; ΣX^2 = 134; Σ(X-X bar)^2=31.6 Compute the 95% confidence interval when X = 4.
6.842, 9.497
A sales manager for an advertising agency believes that there is a relationship between the number of contacts that a salesperson makes and the amount of sales dollars earned. What is the dependent variable?
Amount of sales dollars
In regression analysis, what is the predictor variable called?
Independent variable
If we reject the null hypothesis, H0: p=0, what can we conclude about the population correlation coefficient?
It is not zero
Consider a regression and correlation analysis where r2 = 1. We know that
SSE must equal to zero.
In the regression equation, what does the letter "b" represent?
The slope of the line
The value of the correlation coefficient (r):
can be equal to the value of the coefficient of determination (r^2).
In regression, if the relationship between the dependent and independent variables is non-linear, a linear relationship between the variables can be achieved by:
rescaling the variables.
The regression equation is Ŷ = 29.29 - 0.96X, the sample size is 8, and the standard error of the slope is 0.22. What is the test-statistic to test the significance of the slope?
t = -4.364
The regression equation is Ŷ = 29.29 - 0.96X, the sample size is 8, and the standard error of the slope is 0.22. What is the critical value to test the significance of the slope at the 0.01 significance level?
t = ±3.707
An economist is interested in predicting the unemployment rate based on gross domestic product. Since the economist is interested in predicting unemployment, the independent variable is gross domestic product.
true
The values of a and b in the regression equation are called the regression coefficients.
true*
If all the plots on a scatter diagram lie on a straight line, what is the standard error of estimate?
zero*
What is the general form of the regression equation?
Ŷ = a + (bX)
A sales manager for an advertising agency believes that there is a relationship between the number of contacts that a salesperson makes and the amount of sales dollars earned. A regression analysis shows the following results: Picture What is the regression equation?
Ŷ= -12.201 + 2.195X
