Question 1

A prediction interval for Y is narrower than the corresponding confidence interval for the mean of Y.

Accepted Answer

A) True 
 B)False  False

Question 2

In a sample of n = 36,the critical value of Student's t for a two-tailed test of significance of the slope for a simple regression at α = .05 is

Accepted Answer

A) ±2.938 
B) ±2.724 
C) ±2.032 
D) ±2.074 
A) ±2.938 
B) ±2.724 
C) ±2.032 
D) ±2.074 C

Question 3

A negative value for the correlation coefficient (r)implies a negative value for the slope (b1).

Accepted Answer

A) True 
 B)False  True

Question 4

A local trucking company fitted a regression to relate the travel time (days)of its shipments as a function of the distance traveled (miles).The fitted regression is Time = −7.126 + 0.0214 Distance,based on a sample of 20 shipments.The estimated standard error of the slope is 0.0053.Find the value of tcalc to test for zero slope.

Accepted Answer

A) 2.46 
B) 5.02 
C) 4.04 
D) 3.15 
A) 2.46 
B) 5.02 
C) 4.04 
D) 3.15

Question 5

If you have a strong outlier in the residuals,it may represent a different causal system.

Accepted Answer

A) True 
 B)False

Question 6

A researcher's results are shown below using Femlab (labor force participation rate among females)to try to predict Cancer (death rate per 100,000 population due to cancer)in the 50 U.S.states.     Which statement is valid regarding the relationship between Femlab and Cancer?

Accepted Answer

A) A rise in female labor participation rate will cause the cancer rate to decrease within a state. 
B) This model explains about 10 percent of the variation in state cancer rates. 
C) At the .05 level of significance,there isn't enough evidence to say the two variables are related. 
D) If your sister starts working,the cancer rate in your state will decline. 
A) A rise in female labor participation rate will cause the cancer rate to decrease within a state. 
B) This model explains about 10 percent of the variation in state cancer rates. 
C) At the .05 level of significance,there isn't enough evidence to say the two variables are related. 
D) If your sister starts working,the cancer rate in your state will decline.

Question 7

Simple regression analysis means that

Accepted Answer

A) the data are presented in a simple and clear way. 
B) we have only a few observations. 
C) there are only two independent variables. 
D) we have only one explanatory variable. 
A) the data are presented in a simple and clear way. 
B) we have only a few observations. 
C) there are only two independent variables. 
D) we have only one explanatory variable.

Question 8

If SSR is 2592 and SSE is 608,then

Accepted Answer

A) the slope is likely to be insignificant. 
B) the coefficient of determination is .81. 
C) the SST would be smaller than SSR. 
D) the standard error would be large. 
A) the slope is likely to be insignificant. 
B) the coefficient of determination is .81. 
C) the SST would be smaller than SSR. 
D) the standard error would be large.

Question 9

Which is correct to find the value of the coefficient of determination (R2)?

Accepted Answer

A) SSR/SSE 
B) SSR/SST 
C) 1 − SST/SSE 
A) SSR/SSE 
B) SSR/SST 
C) 1 − SST/SSE

Question 10

"High leverage" would refer to a data point that is poorly predicted by the model (large residual).

Accepted Answer

A) True 
 B)False

Question 11

A news network stated that a study had found a positive correlation between the number of children a worker has and his or her earnings last year.You may conclude that

Accepted Answer

A) people should have more children so they can get better jobs. 
B) the data are erroneous because the correlation should be negative. 
C) causation is in serious doubt. 
D) statisticians have small families. 
A) people should have more children so they can get better jobs. 
B) the data are erroneous because the correlation should be negative. 
C) causation is in serious doubt. 
D) statisticians have small families.

Question 12

Consider the following linear trend equation of an industry's sales: yt = 120 + 12 xt,where t is the time index (t = 1,2,... ,n)and yt is annual sales (in millions of dollars).Which is the most reasonable conclusion?

Accepted Answer

A) We would forecast that sales will increase $12 million in the next year. 
B) We would forecast that sales will increase 12 percent in the next year. 
C) On the average,sales will increase 12/(120 + 12 × 10)= 0.05,or 5 percent next year. 
D) The year-to-year average change will depend on the value of t. 
A) We would forecast that sales will increase $12 million in the next year. 
B) We would forecast that sales will increase 12 percent in the next year. 
C) On the average,sales will increase 12/(120 + 12 × 10)= 0.05,or 5 percent next year. 
D) The year-to-year average change will depend on the value of t.

Question 13

The ordinary least squares regression line always passes through the point (x̄,ȳ).

Accepted Answer

A) True 
 B)False

Question 14

In a sample of n = 23,the critical value of Student's t for a two-tailed test of significance for a simple bivariate regression at α = .05 is

Accepted Answer

A) ±2.229 
B) ±2.819 
C) ±2.646 
D) ±2.080 
A) ±2.229 
B) ±2.819 
C) ±2.646 
D) ±2.080

Question 15

The error term εi in the population regression model yi = β0 + β1 xi + εi is assumed to be

Accepted Answer

A) observable. 
B) autocorrelated. 
C) heteroscedastic. 
D) normally distributed. 
A) observable. 
B) autocorrelated. 
C) heteroscedastic. 
D) normally distributed.

Question 16

The standard error of the regression

Accepted Answer

A) is based on squared deviations from the regression line. 
B) may assume negative values if b1 < 0. 
C) is in squared units of the dependent variable. 
D) may be cut in half to get an approximate 95 percent prediction interval. 
A) is based on squared deviations from the regression line. 
B) may assume negative values if b1 < 0. 
C) is in squared units of the dependent variable. 
D) may be cut in half to get an approximate 95 percent prediction interval.

Question 17

Find the slope of the simple regression of Y on X.

Accepted Answer

A) 2.595 
B) 1.109 
C) −2.221 
D) 1.884 
A) 2.595 
B) 1.109 
C) −2.221 
D) 1.884

Question 18

A fitted regression Profit = 262 + 1.51 Sales (all variables in thousands of dollars)was estimated from a random sample of 15 small coffee kiosks.We can say that

Accepted Answer

A) the slope is too small to be significant. 
B) the intercept does not seem reasonable. 
C) the R2 will be low due to small sample size. 
D) predictions are likely to be underestimated. 
A) the slope is too small to be significant. 
B) the intercept does not seem reasonable. 
C) the R2 will be low due to small sample size. 
D) predictions are likely to be underestimated.

Question 19

If r = .55 and n = 16,then the correlation is significant at α = .05 in a two-tailed test.

Accepted Answer

A) True 
 B)False

Question 20

A predictor that is significant in a one-tailed t-test will also be significant in a two-tailed test at the same level of significance α.

Accepted Answer

A) True 
 B)False

A prediction interval for Y is narrower than the corresponding confidence interval for the mean of Y.

In a sample of n = 36,the critical value of Student's t for a two-tailed test of significance of the slope for a simple regression at α = .05 is

A negative value for the correlation coefficient (r)implies a negative value for the slope (b1).

If you have a strong outlier in the residuals,it may represent a different causal system.

A researcher's results are shown below using Femlab (labor force participation rate among females)to try to predict Cancer (death rate per 100,000 population due to cancer)in the 50 U.S.states. Which statement is valid regarding the relationship between Femlab and Cancer?

Simple regression analysis means that

If SSR is 2592 and SSE is 608,then

Which is correct to find the value of the coefficient of determination (R2)?

"High leverage" would refer to a data point that is poorly predicted by the model (large residual).

A news network stated that a study had found a positive correlation between the number of children a worker has and his or her earnings last year.You may conclude that

Consider the following linear trend equation of an industry's sales: yt = 120 + 12 xt,where t is the time index (t = 1,2,... ,n)and yt is annual sales (in millions of dollars).Which is the most reasonable conclusion?

The ordinary least squares regression line always passes through the point (x̄,ȳ).

In a sample of n = 23,the critical value of Student's t for a two-tailed test of significance for a simple bivariate regression at α = .05 is

The error term εi in the population regression model yi = β0 + β1 xi + εi is assumed to be

The standard error of the regression

Find the slope of the simple regression of Y on X.

A fitted regression Profit = 262 + 1.51 Sales (all variables in thousands of dollars)was estimated from a random sample of 15 small coffee kiosks.We can say that

If r = .55 and n = 16,then the correlation is significant at α = .05 in a two-tailed test.

A predictor that is significant in a one-tailed t-test will also be significant in a two-tailed test at the same level of significance α.

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Multiple Regression

Chi-Square Tests

Filters

Exam 12: Simple Regression

A prediction interval for Y is narrower than the corresponding confidence interval for the mean of Y.

In a sample of n = 36,the critical value of Student's t for a two-tailed test of significance of the slope for a simple regression at α = .05 is

A negative value for the correlation coefficient (r)implies a negative value for the slope (b1).

If you have a strong outlier in the residuals,it may represent a different causal system.

A researcher's results are shown below using Femlab (labor force participation rate among females)to try to predict Cancer (death rate per 100,000 population due to cancer)in the 50 U.S.states. Which statement is valid regarding the relationship between Femlab and Cancer?

Simple regression analysis means that

If SSR is 2592 and SSE is 608,then

Which is correct to find the value of the coefficient of determination (R2)?

"High leverage" would refer to a data point that is poorly predicted by the model (large residual).

A news network stated that a study had found a positive correlation between the number of children a worker has and his or her earnings last year.You may conclude that

Consider the following linear trend equation of an industry's sales: yt = 120 + 12 xt,where t is the time index (t = 1,2,... ,n)and yt is annual sales (in millions of dollars).Which is the most reasonable conclusion?

The ordinary least squares regression line always passes through the point (x̄,ȳ).

In a sample of n = 23,the critical value of Student's t for a two-tailed test of significance for a simple bivariate regression at α = .05 is

The error term εi in the population regression model yi = β0 + β1 xi + εi is assumed to be

The standard error of the regression

Find the slope of the simple regression of Y on X.

A fitted regression Profit = 262 + 1.51 Sales (all variables in thousands of dollars)was estimated from a random sample of 15 small coffee kiosks.We can say that

If r = .55 and n = 16,then the correlation is significant at α = .05 in a two-tailed test.

A predictor that is significant in a one-tailed t-test will also be significant in a two-tailed test at the same level of significance α.

Overview of Statistics

Data Collection

Describing Data Visually

Descriptive Statistics

Probability

Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions and Estimation

One-Sample Hypothesis Tests

Two-Sample Hypothesis Tests

Analysis of Variance

Multiple Regression

Chi-Square Tests

Filters