I need someone that is really good in business statistics. 4 test at 10.00 each

Student ID: 22357317

Exam: 250714RR - Inferences and Linear Regression

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Questions 1 to 20: Select the best answer to each question. Note that a question and its answers may be split across a page break, so be sure that you have seen the entire question and all the answers before choosing an answer.

1. Lily Energy Systems manufacturer's wood-burning heaters and fireplace inserts. One of its systems has an electric blower, which is thermostatically controlled. The blower is designed to automatically turn on when the temperature in the stove reaches 125°F and turn off at 85°F. Complaints from customers indicate that the thermostat control is not working properly. The company feels that the thermostat is acceptable if the variance in the cutoff temperature is less than or equal to 175. The company takes a sample of 24 thermostats and finds that the variance equals 289. The calculated chi-square test statistic and the table value for a 0.05 significance level are A. 37.983, 38.076.

B. 38.076, 38.99.

C. 37.983, 35.172.

D. 35.172, 38.99.

2. The F-statistic in a one-way ANOVA represents the variation A. between the treatments plus the variation within the treatments.

B. within the treatments divided by the variation between the treatments.

C. within the treatments minus the variation between the treatments.

D. between the treatments divided by the variation within the treatments.

3. With larger and larger numbers of categories in chi-square tests, the chi-square distribution takes on the shape of the _______ distribution. A. t-

B. normal

C. binomial

D. Poisson

4. In testing the difference between two population means using two independent samples, we use the pooled variance in estimating the standard error of the sampling distribution of the sample mean difference x̄1 − x̄2 if the

A. sizes are both greater than 30.

B. populations are nonnormal with unequal variances.

C. populations are at least normally distributed with equal variances.

D. ample sizes are both large.

5. An indication of no linear relationship between two variables would be a coefficient of A. determination equal to −1. B. correlation equal to −1. C. determination equal to 1.

D. correlation of 0.

6. A left-tail area in the chi-square distribution equals 0.95. For df = 10, the table value equals A. 18.307.

B. 15.987.

C. 20.483.

D. 3.940.

7. A "best-fit" mathematical equation for the values of two variables, x and y, is called A. regression analysis.

B. errors of prediction.

C. scatter diagram.

D. correlation analysis.

8. A random sample of males and females involved in rear-end accidents results in the following Minitab summary:

What is the standard error of the statistic between the two means?

N MEAN MEDIAN TRMEAN STDEV SEMEAN

FEMALES 33 23.91 20.00 23.38 9.77 1.70

MALES 38 28.87 28.50 28.44 9.67 1.57

A. 4.96

B. 0.897

C. 2.314

D. 1.635

9. A random sample of males and females involved in rear-end accidents results in the following Minitab summary:

What is the value of the test statistic (Z score)?

N MEAN MEDIAN TRMEAN STDEV SEMEAN

FEMALES 33 23.91 20.00 23.38 9.77 1.70

MALES 38 28.87 28.50 28.44 9.67 1.57

A. −4.96 B. 2.32

C. 1.64

D. −2.14

10. In using the ANOVA models, the assumptions made about the data are A. the samples are independent.

B. all 3 assumptions made here about the data.

C. the population distributions are normal.

D. the population variances are equal.

11. The vertical distances between observed and predicted values of y are called A. methods of least squares.

B. errors of prediction.

C. scatterplots.

D. least square lines.

12. Given the significance level 0.05, the F-value for the degrees of freedom, df = (3,7) is A. 4.12.

B. 6.16.

C. 8.89.

D. 4.35.

13. Another name for the residual term in a regression equation is A. random error.

B. homoscedasticity.

C. pooled variances.

D. residual analysis.

14. A balanced experiment requires that A. an equal number of persons or test units receives each treatment.

B. at least two treatment groups be used.

C. the number of treatments equals the number of samples.

D. at least one sample equal size is 30.

15. In testing the difference between two population means using two independent samples, the sampling distribution of the sample mean difference x̄1 − x̄2 is normal if the

A. population sizes are both greater than 30.

B. populations are nonnormal and the sample sizes are large.

C. sizes are both greater than 30.

D. populations are normal.

16. In testing for the equality of two population variances, when the populations are normally distributed, the 10% level of significance has been used. To determine the rejection region, it will be necessary to refer to the F table corresponding to an upper-tail area of A. 0.05.

B. 0.10.

End of exam

C. 0.20.

D. 0.90.

17. A regression analysis between sales (in $1000) and advertising (in $) resulted in the following least squares line: yˆ = 80,000 + 5x. This implies that an increase of _______ in advertising is expected to result in an increase of _______ in sales. A. $1, $5

B. $1, $80,005

C. $1, $5,000

D. $5, $5,000

18. A chi-square test for independence with 8 degrees of freedom results in a test statistic of 18.21. Using the chi-square table, the most accurate statement that can be made about the p-value for this test is that A. 0.10 > p-value > 0.05.

B. 0.05 > p-value > 0.025.

C. 0.025 > p-value > 0.01.

D. p-value < 0.01.

19. In testing a population variance or constructing a confidence interval for the population variance, an essential assumption is that A. the population is uniformly distributed.

B. the population is normally distributed.

C. expected frequencies equal or exceed 5.

D. sample size exceeds 30.

20. What is the slope of the line that passes through the points (−5, −8) and (3,8)? A. ½

B. −2 C. 2

D. −½