Statistics

Part 1 of 16 -

Question 1 of 23

1.0 Points

The data presented in the table below resulted from an experiment in which seeds of 5 different types were planted and the number of seeds that germinated within 5 weeks after planting was recorded for each seed type. At the .01 level of significance, is the proportion of seeds that germinate dependent on the seed type?

Seed Type

Observed Frequencies

Germinated

Failed to Germinate

1

31

7

2

57

33

3

87

60

4

52

44

5

10

19

A.Yes, because the test value 16.86 is greater than the critical value of 13.28

B.Yes, because the test value 16.86 is less than the critical value of 14.86

C.No, because the test value 16.86 is greater than the critical value of 13.28

D.No, because the test value 13.28 is less than the critical value of 16.86

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Question 2 of 23

1.0 Points

The chi-square goodness-of-fit test can be used to test for:

A.difference between population means

B.normality

C.difference between population variances

D.significance of sample statistics

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Part 2 of 16 -

Question 3 of 23

1.0 Points

The marketing manager of a large supermarket chain would like to use shelf space to predict the sales of pet food. For a random sample of 12 similar stores, she gathered the following information regarding the shelf space, in feet, devoted to pet food and the weekly sales in hundreds of dollars. .

Store

1

2

3

4

5

6

Shelf Space

5

5

5

10

10

10

Weekly Sales

1.6

2.2

1.4

1.9

2.4

2.6

Store

7

8

9

10

11

12

Shelf Space

15

15

15

20

20

20

Weekly Sales

2.3

2.7

2.8

2.6

2.9

3.1

Compute the value of the sample correlation coefficient between weekly sales and shelf space.

A.0.684

B.0.308

C.0.827

D.0.652

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Question 4 of 23

1.0 Points

Outliers are observations that

A.disrupt the entire linear trend

B.lie outside the sample

C.render the study useless

D.lie outside the typical pattern of points

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Question 5 of 23

1.0 Points

A correlation value of zero indicates.

A.a perfect linear relationship

B.a weak linear relationship

C.a strong linear relationship

D.no linear relationship

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Part 1 of 16 -

Question 1 of 23

1.0 Points

The data presented in the table below resulted from an experiment in which seeds of 5 different types were planted and the number of seeds that germinated within 5 weeks after planting was recorded for each seed type. At the .01 level of significance, is the proportion of seeds that germinate dependent on the seed type?

Seed Type

Observed Frequencies

Germinated

Failed to Germinate

1

31

7

2

57

33

3

87

60

4

52

44

5

10

19

A.Yes, because the test value 16.86 is greater than the critical value of 13.28

B.Yes, because the test value 16.86 is less than the critical value of 14.86

C.No, because the test value 16.86 is greater than the critical value of 13.28

D.No, because the test value 13.28 is less than the critical value of 16.86

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Question 2 of 23

1.0 Points

The chi-square goodness-of-fit test can be used to test for:

A.difference between population means

B.normality

C.difference between population variances

D.significance of sample statistics

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Part 2 of 16 -

Question 3 of 23

1.0 Points

The marketing manager of a large supermarket chain would like to use shelf space to predict the sales of pet food. For a random sample of 12 similar stores, she gathered the following information regarding the shelf space, in feet, devoted to pet food and the weekly sales in hundreds of dollars. .

Store

1

2

3

4

5

6

Shelf Space

5

5

5

10

10

10

Weekly Sales

1.6

2.2

1.4

1.9

2.4

2.6

Store

7

8

9

10

11

12

Shelf Space

15

15

15

20

20

20

Weekly Sales

2.3

2.7

2.8

2.6

2.9

3.1

Compute the value of the sample correlation coefficient between weekly sales and shelf space.

A.0.684

B.0.308

C.0.827

D.0.652

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Question 4 of 23

1.0 Points

Outliers are observations that

A.disrupt the entire linear trend

B.lie outside the sample

C.render the study useless

D.lie outside the typical pattern of points

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Question 5 of 23

1.0 Points

A correlation value of zero indicates.

A.a perfect linear relationship

B.a weak linear relationship

C.a strong linear relationship

D.no linear relationship

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Part 3 of 16 -

Question 6 of 23

1.0 Points

Serum ferritin is used in diagnosing iron deficiency. In a study conducted recently researchers discovered that in a sample of 28 elderly men the sample standard deviation of serum ferritin was 52.6 mg/L. For 26 younger men the sample standard deviation was 84.2 mg/L. At the .01 level of significance, do these data support the conclusion that the ferritin distribution in elderly men has a smaller variance than in younger men?

A.No, because the test value 1.60 is less than the critical value of 2.54

B.Yes, because the test value 2.56 is greater than the critical value of 2.54

C.Yes, because the test value 2.56 is greater than the critical value 0.394

D.Yes, because the test value 0.390 is less than the critical value 2.54

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Question 7 of 23

1.0 Points

Q-Mart is interested in comparing its male and female customers. Q-Mart would like to know if the amount of money spent by its female charge customers differs, on average, from the amount spent by its male charge customers. To answer this question, an analyst collected random samples of 25 female customers and 22 male customers. Based on these samples, on average, the 25 women charge customers spent $102.23 and the 22 men charge customers spent $86.46. Moreover, the sample standard deviation of the amount charged by the 25 women was $93.393, and the sample standard deviation of the amount charged by the 22 men was $59.695. Using the procedure advocated by Bluman, at the 10% level of significance, is there sufficient evidence for Q-Mart to conclude that, on average, the amount spent by women charge customers differs from the amount spent by men charge customers.

A.No, the test value does not exceed the critical value.

B.Yes, the p-value of this test is greater than 0.10

C.No, the p-value of this test is less than 0.10.

D.Yes, the test value does not exceed the critical value

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Part 4 of 16 -

Question 8 of 23

1.0 Points

Which of the following statements are true of the null and alternative hypotheses?

A.Both hypotheses must be true

B.It is possible for both hypotheses to be true

C.It is possible for neither hypothesis to be true

D.Exactly one hypothesis must be true

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Question 9 of 23

1.0 Points

A manufacturer of flashlight batteries took a sample of 13 batteries from a day’s production and used them continuously until they failed to work. The life lengths of the batteries, in hours, until they failed were: 342, 426, 317, 545, 264, 451, 1049, 631, 512, 266, 492, 562, and 298.

At the .05 level of significance, is there evidence to suggest that the mean life length of the batteries produced by this manufacturer is more than 400 hours?

A.Yes, because the test value 1.257 is less than the critical value 1.782

B.Yes, because the test value 1.257 is less than the critical value 2.179

C.No, because the test value 1.257 is greater than the critical value 1.115

D.No, because the p-value for this test is equal to .1164

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Question 10 of 23

1.0 Points

Results from previous studies showed 79% of all high school seniors from a certain city plan to attend college after graduation. A random sample of 200 high school seniors from this city reveals that 162 plan to attend college. Does this indicate that the percentage has increased from that of previous studies? Test at the 5% level of significance. State the null and alternative hypotheses.

A.H0: p ≤ .79, H1: p > .79

B.H0:  = .79, H1:  > .79

C.

H0: = .79, H1: > .79

D.H0: p = .79, H1: p ≠ .79

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Part 5 of 16 -

Question 11 of 23

1.0 Points

Confidence intervals are a function of which of the following three things?

A.The data in the sample, the confidence level, and the sample size

B.The population, the sample, and the standard deviation

C.The sample, the variable of interest, and the degrees of freedom

D.The sampling distribution, the confidence level, and the degrees of freedom

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Question 12 of 23

1.0 Points

In order to be accepted into a top university, applicants must score within the top 5% on the SAT exam. Given that SAT test scores are normally distributed with a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university?

A.1330

B.1400

C.1250

D.1100

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Part 6 of 16 -

Question 13 of 23

1.0 Points

The mean of a probability distribution can be:

A.a positive number

B.a negative number

C.zero

D.all of the above

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Part 7 of 16 -

Question 14 of 23

1.0 Points

Find the variance of the following probability distribution.

X

P(X)

1

0.30

2

0.15

3

0.05

4

0.25

5

0.25

A.1.73

B.1.61

C.2.60

D.1.27

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Part 8 of 16 -

Question 15 of 23

1.0 Points

If one tosses a coin enough times, the proportion of "heads" will approach 0.5. This is an example of:

A.the Law of Large Numbers

B.the Empirical Rule

C.subjective probabilities

D.the Central Limit Theorem

Part 9 of 16 -

Question 16 of 23

3.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Staples, a chain of large office supply stores, sells a line of desktop and laptop computers. Company executives want to know whether the demands for these two types of computers are dependent on one another. Each day's demand for each type of computers is categorized as Low, Medium-Low, Medium-High, or High. The data shown in the table below is based on 200 days of operation. Based on these data, can Staples conclude that demands for these two types of computers are independent? Test at the 5% level of significance.

desktops

low

med-low

med-high

high

low

3

14

14

4

35

laptops

med-low

6

18

17

22

63

med-high

13

16

11

16

56

high

8

14

15

9

46

30

62

57

51

200

What is the test value for this hypothesis test? Answer:

Round your answer to two decimal places. What is the critical value for this hypothesis test? Answer:

Round your answer to two decimal places. What is the conclusion for this hypothesis test? Choose one. 1. At the .05 level of significance, Staples can conclude that demands for these two types of computers are independent. 2. At the .05 level of significance, Staples can conclude that demands for these two types of computers are dependent. Answer:

Enter only a 1 or 2 for your answer.

Question 18 of 23

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. An investor wants to compare the risks associated with two different stocks. One way to measure the risk of a given stock is to measure the variation in the stock’s daily price changes. In an effort to test the claim that the variance in the daily stock price changes for stock 1 is different from the variance in the daily stock price changes for stock 2, the investor obtains a random sample of 21 daily price changes for stock 1 and 21 daily price changes for stock 2. The summary statistics associated with these samples are: n1 = 21, s1 = .848, n2 = 21, s2 = .529. If you follow Bluman's advice and place the larger variance in the numerator when computing the test value, at the .05 level of significance, what is the critical value associated with this test of hypothesis? Place your answer, rounded to 2 decimal places, in the blank. For example, 3.45 would be a legitimate entry.

Part 12 of 16 -

Question 19 of 23

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. Mrs. Smith's reading class can read a mean of 175 words per minute with a standard deviation of 20 words per minute. The top 3% of the class is to receive a special award. Assuming that the distribution of words read per minute are normally distributed, what is the minimum number of words per minute a student would have to read in order to get the award? Place your answer, rounded to the nearest whole number, in the blank.

When entering your answer do not use any labels or symbols. Simply provide the numerical value. For example, 123 would be a legitimate entry.

Part 13 of 16 -

Question 20 of 23

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The personnel department of a large corporation wants to estimate the family dental expenses of its employees to determine the feasibility of providing a dental insurance plan. A random sample of 12 employees reveals the following family dental expenses (in dollars): 115, 370, 250, 593, 540, 225, 177, 425, 318, 182, 275, and 228. Construct a 99% confidence interval estimate for the standard deviation of family dental expenses for all employees of this corporation. Place your LOWER limit, in dollars rounded to 1 decimal place, in the first blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 98.4 would be a legitimate entry.

Place your UPPER limit, in dollars rounded to 1 decimal place, in the second blank. Do not use a dollar sign, a comma, or any other stray mark. For example, 567.8 would be a legitimate entry.

Question 21 of 23

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A DVD rental business determines that customers will rent X number of DVDs according to the following distribution:

Number of DVDs rented X

1

2

3

4

5

Probability P(X)

0.15

0.25

0.3

0.25

0.05

What is the mean number of DVDs that customers rent? Round your answer to one decimal place as necessary. For example, 4.5 would be a legitimate entry. Answer:

Part 15 of 16 -

Question 22 of 23

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. The CEO of a software company is committed to expanding the proportion of highly qualified women in the organization’s staff of salespersons. He believes that the proportion of women in similar sales positions across the country is less than 45%. Hoping to find support for his belief, he directs you to test H0: p .45 vs H1: p < .45. In doing so, you collect a random sample of 50 salespersons employed by his company, which is thought to be representative of sales staffs of competing organizations in the industry. The collected random sample of size 50 showed that only 18 were women. Compute the p-value associated with this test. Place your answer, rounded to 4 decimal places, in the blank. For example, 0.3456 would be a legitimate entry.

Part 16 of 16 -

Question 23 of 23

1.0 Points

Accepted characters: numbers, decimal point markers (period or comma), sign indicators (-), spaces (e.g., as thousands separator, 5 000), "E" or "e" (used in scientific notation). NOTE: For scientific notation, a period MUST be used as the decimal point marker. Complex numbers should be in the form (a + bi) where "a" and "b" need to have explicitly stated values. For example: {1+1i} is valid whereas {1+i} is not. {0+9i} is valid whereas {9i} is not. A bag contains 12 colored balls, each ball being either black or white. The probability of drawing a white ball twice with replacement is 1/16. How many white balls are in the bag? Place your answer in the blank, do not include any decimals or other marks. For example, 7 would be a legitimate entry. There are

white balls in the bag.