1 For a test of a mean, which of the following isincorrect?

H₀is rejected when the calculatedp-value is greater than the critical value of the test statistic.

In a right-tailed test, we rejectH₀when the test statistic exceeds the critical value.

The critical value is based on the researcher's chosen level of significance.

IfH₀: 100 andH₁:> 100, then the test is right-tailed.

2 GivenH₀: 18 andH₁:< 18, which of the following is correct:

The test is two tailed

The test is left tailed.

The test is right tailed.

3 A two-tailed hypothesis test forH₀:= .30 at= .05 is analogous to

asking if the 90 percent confidence interval forcontains .30.

asking if the 95 percent confidence interval forcontains .30.

asking if thep-value (area in both tails combined) is less than .025.

asking if thep-value (area in both tails combined) is less than .10.

4 In a random sample of patient records in Cutter Memorial Hospital, six-month postoperative exams were given in 90 out of 200 cases, the sample proportion is:

.45

.40

.30

.20

5 Two well-known aviation training schools are being compared using random samples of their graduates. It is found that 70 of 140 graduates of Fly-More Academy passed their FAA exams on the first try, compared with 104 of 260 graduates of Blue Yonder Institute. In a right-tailed test, thep-value is .0275, so at= .025 we should:

reject the hypothesis of equal proportions.

not reject the hypothesis of equal proportions.

change theto .05 to get a rejection.

6 Carver Memorial Hospital's surgeons have a new procedure that they think will decrease the time to perform an appendectomy. A sample of 8 appendectomies using the old method had a mean of 38 minutes with a variance of 36 minutes, while a sample of 10 appendectomies using the experimental method had a mean of 29 minutes with a variance of 16 minutes. For a right-tail test for equal means (assume equal variances), the critical value at= .10 is:

1.746

1.337

2.120

2.754

7 Which is indicative of an inverse relationship betweenXandY?

A negativeFstatistic

A negativep-value for the correlation coefficient

A negative correlation coefficient

Either a negativeFstatistic or a negativep-value

8 Which statement is correct?

Autocorrelation is mainly a concern if we are using time-series data.

Heteroscedastic residuals will have roughly the same variance for any value ofX.

Non normality is assumed under ordinary least squares regression.

9 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 isTime= -7.126 + 0.0214Distance. IfDistanceincreases by 50 miles, the expectedTimewould increase by:

1.07 days

7.13 days

2.14 days

1.73 days

10 A multiple regression with 60 observations should not have 13 predictors.

True

False

11 Multicollinearity can be detected fromttests of the predictor variables.

True

False

12 The R-square value from your regression output is .34, which of the following statement is true:

The null hypothesis should be rejected since .34 is greater than alpha

An increase of 1% in the independent variable will cause a 34% increase in the dependent variable.

34% of the variation in the dependent variable can be explained by the variation in the independent variable.

13 You are a data analyst for a major auto corporation. You are tasked with estimating the fuel economy of a certain engine that goes in multiple vehicle models. You estimate the regression equation:Economy=49.032-.0218*weight+5.67*fuelsaver.Fuelsaver is a binary variable (it is a 1 if the vehicle has fuelsaver technology, 0 otherwise). Predict the fuel efficiency of a 1350 lb vehicle with fuelsaver technology.

.48.332

25.272

30.782

34.512

14 In a regression with 60 observations and 7 predictors, there will be _____ residuals.

60

59

52

6

15 You are studying the growth of adolescent males. Your correlation matrix of your independent variables shows a significant strong positive correlation between predictor variables "musclemass" and "musclediameter." Which is the correct next step.

Throw out musclediameter in favor of musclemass due to the strong significant correlation

Examine the variance inflation factors to determine if the stability of the regression is compromised

Run a "stepwise" regression to determine the best course of action

Any variance inflation factor below 10 should be considered to effect the stability of the regression.

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