test 1 app and opp

Louis Katz, a cost accountant at Papalote Plastics, Inc. (PPI), is analyzing the manufacturing costs of a molded plastic telephone handset produced by PPI. Louis's independent variable is production lot size (in 1,000's of units), and his dependent variable is the total cost of the lot (in $100's). Regression analysis of the data yielded the following tables. question 22

.73

In the regression equation, y = 49.56 + 0.97x, the slope is _______.

.97

Louis Katz, a cost accountant at Papalote Plastics, Inc. (PPI), is analyzing the manufacturing costs of a molded plastic telephone handset produced by PPI. Louis's independent variable is production lot size (in 1,000's of units), and his dependent variable is the total cost of the lot (in $100's). Regression analysis of the data yielded the following tables. question 23

13

A researcher has developed a regression model from fourteen pairs of data points. He wants to test if the slope is significantly different from zero. He uses a two- tailed test and α = 0.01. The critical table t value is _______.

3.055

The following regression model was fitted to sample data with 12 observations: ŷ= 30 + 4.50x. What is the change in the predicted value of y for a unit change in the value?

4.50

Louis Katz, a cost accountant at Papalote Plastics, Inc. (PPI), is analyzing the manufacturing costs of a molded plastic telephone handset produced by PPI. Louis's independent variable is production lot size (in 1,000's of units), and his dependent variable is the total cost of the lot (in $100's). Regression analysis of the data yielded the following tables. question 26

757.60

Some entries have been deleted from the following analysis of variance table that is part of the computer output from a simple regression analysis of a data set containing 11 matched-pair observations. based on this output what is the value of the F statistic question 37

9.4022

8) A study on 77 breakfast cereals concludes that high fiber cereals are lower in calories. A scatterplot for the 77 cereals used is provided below.which statement is true?

A.. Some high leverage points are evident, and there is a strong positive association between amount of fiber and number of calories per serving.

5) A standard deviation of the error of the regression model is called the _____.

B. Standard error of estimate

4)A hospital administrator developed a regression line, y = 30 + 2x, to predict the number of full-time employees (FTE) needed using the number of beds. The slope of this regression line suggests this: ___

B. for a unit increase in the number of beds, the number of FTEs is predicted to increase by 2

12) A graphical tool to illustrate the relationship between matched observations of two variables (e.g. y = the annual cost of operating a commercial airliner and x = the annual number of passengers served by the airline), is _____.

B. scatter plot

15) If the plot of the residuals is cone shaped, which assumption is violated?

C. Homoscedasticity

13) Accoding to the following graphic, X and Y have ______.

C. virtually no correlation

7)Annie's regression model can be written as: ____

C. y = -.14156 + .105195x

14) Which of the following statement(s) is/are correct? i. The width of the prediction interval for the predicted value of Y is dependent on the standard error of the estimate, the value of X for which the prediction is being made, and the sample size. ii. The range of the prediction interval is always wider than the range of the confidence interval for the same X value. iii. Confidence interval is an estimate of a single value of Y for a given X.

D. I and II

1) Which of the following description is WRONG?

D. It is best to use PEarson correlation to measure the strength of the non-linear association between two variables

20) If x and y in a regression model are totally unrelated, _______.

D. the coefficient of determination would be 0

3)The least squares method minimizes which of the following?

D.SSE

18) If a B-school wants to predict or forecast the graduating GPA of entering freshmen (an unknown variable of interest), it might look at, among other things, their SAT scores ( a known variable). Which of the following statement does NOT represent this situation?

E. GPA is a fixed variables and does not vary among graduating student

16) Which of the following description is WRONG?

E. If the correlation coefficient between two variables is -1, it means that the two variables are not related

6) Which of the following statement is WRONG?

E. The degree of freedom in regression is equal to the number of observation

19) The following residuals plot indicates_____.

E. nonlinear relation

17) Annie's sample size is ______.

E.6

10) Which of the following statements are right?i. The first step in simple regression analysis usually is to construct a scatter plot. ii. In simple regression analysis, the error terms are assumed to be linear, independent, and normally distributed with zero mean and constant variance. iii. The proportion of variability of the dependent variable (y) accounted for or explained by the independent variable (x) is called the coefficient of correlation.

a) I and II

A quality manager is developing a regression model to predict the total number of defects as a function of the day of week the item is produced. Production runs are done 10 hours a day, 7 days a week. The explanatory variable is ______.

day of week

In the simple regression model, y = 21 − 5x, if the coefficient of determination is 0.81, we can say that the coefficient of correlation between y and x is 0.90. t/f

false

One of the assumptions of simple regression analysis is that the error terms are exponentially distributed t/f

false

Prediction intervals get narrower as we extrapolate outside the range of the data. t/f

false

Regression output from Excel software directly shows the regression equation. t/f

false

The F-value to test the overall significance of a regression model is computed by dividing the sum of squares regression (SSreg) by the sum of squares error (SSerr). t/f

false

The slope of the regression line, y = 21 − 5x, is 21. t/f

false

The slope of the regression line, y = 21 − 5x, is 5. t/f

false

The standard error of the estimate, denoted se, is the square root of the sum of the squares of the vertical distances between the actual Y values and the predicted values of Y. t/f

false

The strength of a linear relationship in simple linear regression change if the units of the data are converted, say from feet to inches. t/f

false

The variability in the estimated slope is smaller when the x-values are more spread out. t/f

false

A cost accountant is developing a regression model to predict the total cost of producing a batch of printed circuit boards as a linear function of batch size (the number of boards produced in one lot or batch). The intercept of this model is the ______.

fixed cost

A hospital administrator developed a regression line, y = 30 + 2x, to predict y = the number of full-time employees (FTE) needed using x = the number of beds. The slope of this regression line suggests this: __________.

for a unit increase in the number of beds, the number of FTEs is predicted to increase by 2

if the error variances of a regression model are not constant, it is called _________

heteroscedasticity

The assumption of constant error variance in regression analysis is called _______.

homoscedasticity

Louis Katz, a cost accountant at Papalote Plastics, Inc. (PPI), is analyzing the manufacturing costs of a molded plastic telephone handset produced by PPI. Louis's independent variable is production lot size (in 1,000's of units), and his dependent variable is the total cost of the lot (in $100's). Regression analysis of the data yielded the following tables. question 24

reject H0: β1 = 0

least squares regression line is one that______

results in the smallest sum of errors squared

a standard deviation of the error of the regression model is called the

standard error of the estimate

According to the following graphic, X and Y have _________. quesiton 1

strong positive correlation

One of the assumptions made in simple regression is that ______________.

the error terms are normally distributed

which of the following is not an assumption of the regression model?

the error terms decrease as x values increase

In simple regression analysis the error terms are assumed to be independent and normally distributed with zero mean and constant variance. t/f

true

One of the major uses of residual analysis is to test some of the assumptions underlying regression. t/f

true

Regression output from Excel software includes an ANOVA table. t/f

true

The coefficient of determination is the proportion of variability of the dependent variable (y) accounted for or explained by the independent variable (x). t/f

true

The difference between the actual y value and the predicted y value found using a regression equation is called the residual. t/f

true

The process of constructing a mathematical model or function that can be used to predict or determine one variable by another variable is called regression analysis. t/f

true

To determine whether the overall regression model is significant, the F-test is used. t/f

true

From the following scatter plot, we can say that between y and x there is _______. question 2

vitually no correlation

Suppose we are making predictions of the dependent variable y for specific values of the independent variable x using a simple linear regression model holding the confidence level constant. Let Width (C.I) = the width of the confidence interval for the average value y for a given value of x, and Width (P.I) = the width of the prediction interval for a single value y for a given value of x. Which of the following statements is true?

width (C.I)< width (P.I)

Louis Katz, a cost accountant at Papalote Plastics, Inc. (PPI), is analyzing the manufacturing costs of a molded plastic telephone handset produced by PPI. Louis's independent variable is production lot size (in 1,000's of units), and his dependent variable is the total cost of the lot (in $100's). Regression analysis of the data yielded the following tables. question 21

y=3.966+.358x

If the standard error of the estimate for a regression model fitted to a large number of paired observations is 1.75, approximately 68% of the residuals would lie within ______

-1.75 and +1.75

The coefficient of correlation in a simple regression analysis is = - 0.6. The coefficient of determination for this regression would be _______.

.36

Suppose your fit a least squares line to 25 data points and the calculated value of SSE is 8.56, what is the estimation of the variance (σ2) of the random error term?

.372

in a regression analysis if SST= 200 and SSR= 200, R^2 = ______

1

11) For the following scatter plot and regression line, at x = 48 the residual is ____.

A. positive

If a B-school wants to predict or forecast the graduating GPA of entering freshmen (an unknown variable of interest), it might look at, among other things, their SAT scores (a known variable). Which of the following statements does not represent this situation?

GPA is a fixed variable and does not vary among graduating students

the following residuals plot indicate question 13

a non constant error variance

the following residual plot indicates question 14

a non liniar relation

9)) Using alpha = .05, Annie should_____.

a.)Reject H0: B1 = 0

2) For certain data set the regression equation is y = 29x - 5. The correlation coefficient between y and x in this data set is _____.

c. is negative

The proportion of variability of the dependent variable accounted for or explained by the independent variable is called the _______.

coefficient of determination

Data points that lie apart from the rest of the points are called deviants. t/f

false

If the correlation coefficient between two variables is -1, it means that the two variables are not related. t/f

false

In a simple regression the coefficient of correlation is the square root of the coefficient of determination. t/f

false

In regression, the predictor variable is called the dependent variable. t/f

false

In regression, the variable that is being predicted is usually referred to as the independent variable. t/f

false

The proportion of variability of the dependent variable (y) accounted for or explained by the independent variable (x) is called the coefficient of correlation. t/f

false

The range of admissible values for the coefficient of determination is −1 to +1. t/f

false

For a certain data set the regression equation is y = 29 - 5x. The correlation coefficient between y and x in this data set _______.

is negative

The values of b0 and b1 in a regression equation are determined using sample data through a process called __________.

least squares analysis

a value of -1 for the coefficient of correlation between two variables means that the two variables are_______

perfectly related

Consider the following scatter plot and regression line. At x = 50, the residual (error term) is _______. question 10

positive

If there is perfect negative correlation between two sets of numbers, then _______.

r=-1

If there is positive correlation between two sets of numbers, then _______.

r>0

the total of the squared residual is called the

sum f squares of error

if x and y in a regression model are totally un related,________

the coefficient of determination would be 0

the assumptions underlying simple regression analysis include__________

the error terms are independent

A t-test is used to determine whether the coefficients of the regression model are significantly different from zero. t/f

true

Correlation is a measure of the degree of linear relationship between two variables. t/f

true

For the regression line, y = 21 − 5x, 21 is the y-intercept of the line. t/f

true

Given x, a 95% prediction interval for a single value of y is always wider than a 95% confidence interval for the average value of y. t/f

true

Which of the following equations represents a linear relationship between y and x?

y=mx+b