25Q

DUE: FRIDAY April 7, 2017 – BEFORE midnight (11:59pm)

Late submissions will NOT be accepted.

This is an INDIVIDUAL assignment.

Content: Chapters 11, 12, 15 & 16

Please follow ALL instructions

QUESTIONS 1 through 25:

Submit your responses via Bb for Lab 4 – you are just entering

your answers to the M/C questions here (0.80 mark each = total 20

marks)

Do NOT access the dropbox until you have formulated your answers to

this lab! The dropbox will open in a few days.

You can override dropbox submissions until the deadline.

NOTE: Given complexity of symbols/responses below, answers in

Blackboard may not look exactly as in the Instructions version, but will be

clearly in same order and be identifiable

There is only one part to this lab – 25 Multiple Choice questions

Good Luck!

BUSI 1450 – Statistics (Winter 2017) Lab #4 – Questions & Instructions

DUE: Friday April 7, 2017 – BEFORE midnight (11:59pm)

1. Suppose a regression model for the price of concrete for a driveway is:

Every extra square yard of concrete is expected to add how much to the price for the driveway?

a. $500

b. $10

c. $510

d. {There is not sufficient information to answer the question}

2. Suppose an alternative regression model for the price of adding concrete to a driveway is:

$450 + ($8 × squareyard of concrete) + ($3 × cubic metres of sand underfill)

What is the b0 term for this formula?

a. $11

b. $8.

c. $3.

d. $450.

e. $472

Use this table for answering questions 3 to 11

TABLE 1. For a sample of students who have taken standardized university entrance exams, the

students’ corresponding scores for the Verbal and Math questions were compared. These are the

results.

Verbal

Score

623 454 643 585 719 693 571 646 613 655 662 585 580 506 669

Math

Score

509 471 700 619 710 643 665 719 693 701 614 557 611 600 653

3. Refer to Table 1. What is the “r” value, for the correlation between students’ Verbal scores and their

Math scores?

a. 0.646

b. 0.009

c. 0.151

d. 0.418

e. 0.155

4. Refer to Table 1. Which best describes the correlation between students’ Verbal scores and their

corresponding Math scores?

a. Virtually no correlation

b. A very strong positive correlation

c. A moderate positive correlation

d. A strong negative correlation

e. A moderate negative correlation

BUSI 1450 – Statistics (Winter 2017) Lab #4 – Questions & Instructions

DUE: Friday April 7, 2017 – BEFORE midnight (11:59pm)

5. Refer to Table 1. Is there a significant correlation between students’ Verbal scores and their

corresponding Math scores; and how does one decide this?

a. Yes; based on Pearson correlation

b. No; based on Pearson correlation

c. No; based on p-value

d. Yes; based on p-value

6. Refer to Table 1. If a regression equation is developed for a student’s Verbal score based on his or

her Math score, it could look like this:

(Note: Let y = Verbal Score; x1 = Math Score)

a. 0.608 + 230×1

b. 210 + 0.687×1

c. -2.26 + -1.15×1

d. 230 + 0.608×1

7. Refer to Table 1. If we use the regression that estimates a student’s Verbal score based on his or

her Math score, what portion of the variance in the dependent variable is explained by the

regression?

a. 37.3%

b. 41.8%

c. 55.3%

d. 14.54%

e. {None of the other answers is approximately correct.}

8. Refer to Table 1. If we use the regression that estimates a student’s Verbal score based on his or her

Math score, what is the standard error of the estimate?

a. 55.3

b. 41.8

c. 58.7

d. 126

e. {None of the other answers is approximately correct.}

9. Refer to Table 1. Based on the regression that estimates a student’s Verbal score based on his or her

Math score, what is the approximate point estimate for Verbal Score if the Math Score was 720?

a. 668

b. 166

c. 705

c. {None of the other answers is approximately correct.}

10. Refer to Table 1, but convert both the Verbal Scores and the Math Scores to ranks. What is the rs between the ranks for these two variables?

a. 0.646

b. 0.104

c. 0.027

d. 0.568

BUSI 1450 – Statistics (Winter 2017) Lab #4 – Questions & Instructions

DUE: Friday April 7, 2017 – BEFORE midnight (11:59pm)

11. Refer to Table 1, but convert both the Verbal Scores and the Math Scores to ranks. What is the

p-value for the Spearman’s rank correlation coefficient between these variables?

a. 0.646

b. 0.009

c. 0.027

d. 0.568

Questions 12 to 15 are based on this information:

 Emily claims that the mean height of NBA basketball players is greater than 6.50 feet. According to data from the NBA website, the standard deviation for all NBA players’

heights is about 0.19 feet.

 Michael studies statistics, and wants to formally test Emily’s claim, at the 0.01 level of significance. Michael samples 35 NBA players, and for this sample, the mean height is

6.589 feet.

12. In the above problem, what would be the correct statistical test for Michael to use:

a. One-sample t test for the mean

b One-sample z test for the mean

c One-sample p test for the mean

d Two-sample t test for the mean

e Two-sample z test for the mean

13. In the above problem, what should Michael use as the null hypothesis?

a H0: µ ≤ 6.50 feet

b H0: µ > 6.50 feet

c H1: µ > 6.50 feet

d H1: µ ≤ 6.50 feet

e α = 0.01

14. If Michael uses the critical value method for the hypothesis test described above, what is the

value for the test statistic?

a. 0.089 b. z= 2.771 c. t = 2.771 d. t = 2.731 e. 6.589

15. Based on the information given in the problem written above Question 12, what would be the correct statistical decision for Michael’s hypothesis test?

a. Emily’s claim is supported. b. Do not reject H0. c. Do reject H0. d. {There is not enough information to answer the question.}

BUSI 1450 – Statistics (Winter 2017) Lab #4 – Questions & Instructions

DUE: Friday April 7, 2017 – BEFORE midnight (11:59pm)

16. When developing a good regression model in multiple linear regression, it is a good idea to:

a. use as many independent variables as you can

b. omit any highly influential variables

c. keep things simple

d. maximize collinearity

17. A manufacturer owns factories in three cities. Each factory produces two products: Hairspray and After Shave Lotion. At random times, the manager went to each of his factories, and

recorded how many cartons of each product category were produced. These were the

results:

Hairspray After Shave Lotion Total

Factory A 53 57 110

Factory B 32 43 75

Factory C 78 101 179

Total 163 201 364

The manager claims that the proportions of the two products being produced (Hairspray versus

After Shave Lotion) are not the same at all the factories. He’ll test this claim at the 0.05 level

of significance.

Which of the following tests is most appropriate for testing the manufacturer’s claim?

a. Wilcoxon signed-ranks test

b. Chi-square test for Association

c. Two-way Analysis of Variance

d. t test for the mean (three samples)

e. Chi-square test for goodness of fit

18. If the Manager in question 17 performs the appropriate hypothesis test for his claim, what p- value should be obtained?

a. 0.755 b. 0.993 c. 0.686

d. 2

e. {None of the other answers are approximately correct}

BUSI 1450 – Statistics (Winter 2017) Lab #4 – Questions & Instructions

DUE: Friday April 7, 2017 – BEFORE midnight (11:59pm) 19. A booklover plans to reluctantly switch from buying hardcover novels to “kindle” electronic

versions, because she claims that Kindle versions are generally cheaper than their

corresponding hardcopy versions. She collects these data to test her claim using the 0.05

level of significance.

Which of the following tests is most appropriate for testing the booklover’s claim?

a. t-test for the difference in population means, two independent samples

b. t-test for the difference in population means, two dependent samples

c. Two-way Analysis of Variance

d. F test for the mean (three samples)

e. Chi-square test for goodness of fit

20. If the booklover in Question 19 performs the appropriate hypothesis test for her claim, using the 8-step approach in this course, what should be answer to Step 8?

a. The data support her claim. b. The data do not support her claim. c. Reject the null hypothesis.

d. Do not reject the null hypothesis

e. Accept the null hypothesis

21. The drying times for a certain type of cement are normally distributed with a standard deviation of 28 minutes. A researcher wishes to estimate the mean drying time for this type of

cement. Find the minimum sample size needed to estimate the mean drying time (within 5

minutes above or below the true value) with 93% confidence.

a) 102 b) 57 c) 103 d) 515 e) 30

22. A quality control manager wants to estimate what proportion of items shipped get returned by customers. Traditionally, the proportion of returned items has been 6%. Find the minimum

sample size needed to estimate the proportion of items returned (with a margin of error of 3%)

with 95% confidence.

a) 1229 b) 2027 c) 2407 d) 2028 e) 2408

BUSI 1450 – Statistics (Winter 2017) Lab #4 – Questions & Instructions

DUE: Friday April 7, 2017 – BEFORE midnight (11:59pm)

23. A construction company tested two chain saw blade sharpeners, method A and method B, sold by two different companies. Each of 10 randomly selected volunteers sharpened a package of 12

blades using method A and another sample of 10 randomly selected volunteers each sharpened a

package of 12 blades using method B.

It took method A an average of 203 seconds to sharpen a blade with a standard deviation of 6

seconds. It took method B an average of 187 seconds to sharpen a blade with a standard

deviation of 5 seconds. Assume that the sharpening times for both methods A and B are

normally distributed with equal and unknown standard deviations.

What is the 99% confidence interval for the difference in the mean sharpening times of method

A and method B?

a. 187 to 203 b. 10.750 to 21.250 c. 8.567 to 24.878 d. 8.892 to 23.108

24. A company claims that its course to prepare foreign doctors to write the Certification Examination in Family Medicine significantly increases student marks on the exam. Eight

students wrote prepared Certification Examination in Family Medicine exams before and after

taking the short course. The results are shown in the table reporting the number of questions

marked correct out of a set number of 30. Assume a normal distribution of the paired

differences (***Note: This test will use after minus before for the differences) .

Student 1 2 3 4 5 6 7 8

After 21 24 23 25 24 28 24 23

Before 23 26 19 24 27 22 20 18

Referring to the above narrative, what are the null and alternative hypotheses?

a. H0: μd ≤0 H1: μd >0 b. H0: μd ≥0 H1: μd <0 c. H0: μd <0 H1: μd ≥0 d. H0: μd =0 H1: μd ≠0 e. The hypotheses cannot be known without being provided a level of significance

25. Referring to the data in question 24, what is the test statistic?

a. 1.28 b. 0.45 c. 2.82 d. 1.63 e. The test statistic cannot be known without being provided a level of significance

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