Project #11012 - stastistics

 

Question 1 of 23

1.0 Points

 

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

 

 

 

 

 

 A.normality  

 B.difference between population variances

 

 C.difference between population means

 

 D.significance of sample statistics

 

 

 

 

Question 2 of 23

1.0 Points

 

A company operates four machines during three shifts each day. From production records, the data in the table below were collected. At the .05 level of significance test to determine if the number of breakdowns is independent of the shift.

 

 

 

 

Machine

Shift

A

B

C

D

1

41

20

12

16

2

31

11

9

14

3

15

17

16

10

 

 

 

 

 

 

 

 A.The number of breakdowns is dependent on the shift, because the test value 11.649 is less than the critical value of 12.592.

 

 B.The claim that the number of breakdowns is independent of the shift cannot be rejected, because the test value 11.649 is less than the critical value of 12.592.

 

 C.The number of breakdowns is dependent on the shift, because the p-value is .07.

 

 D.The number of breakdowns is independent of the shift, because the test value 12.592 is greater than the critical value of 11.649.

 

 

Question 3 of 23

1.0 Points

In a simple linear regression analysis, the following sum of squares are produced: 

f$sum{(y-ar{y})^{2}}f$ = 500

f$sum{(y-y')^{2}}f$ = 100

f$sum{(y'-ar{y})^{2}}f$ = 400

The proportion of the variation in Y that is explained by the variation in X is:

 

 

 A.20%

 

 B.25%

 

 C.80%

 

 D.50%

 
 

 

 

 

Question 4 of 23

1.0 Points

Correlation is a summary measure that indicates:

 

 

 A.a curved relationship among the variables

 

 B.the magnitude of difference between two variables

 

 C.the strength of the linear relationship between pairs of variables

 

 D.the rate of change in Y for a one unit change in X

 

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Question 5 of 23

1.0 Points

An agent for a residential real estate company in a large city would like to be able to predict the monthly rental cost of apartments based on the size of the apartment. Data for a sample of 25 apartments in a particular neighborhood are provided in the worksheet Apartments in the Excel workbook Apartments.xlsx. 

Apartments.xlsx

At the .05 level of significance determine if the correlation between rental cost and apartment size is significant.

 

 

 A.No, there is not a statistically significant linear relationship between monthly rental cost and apartment size, because the sample correlation coefficient is less than .95.

 

 B.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the t-test value, 7.74, is greater than the critical value 1.96.

 

 C.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the p-value for this test is less than .0001.

 

 D.Yes, there is a statistically significant linear relationship between monthly rental cost and apartment size, because the sample correlation coefficient 0.85 exceeds 0.50.

 

Question 6 of 23

1.0 Points

Two independent samples of sizes n1 = 50 and n2 = 50 are randomly selected from two populations to test the difference between the population means, f$mu_{1}-mu _{2}f$  . The sampling distribution of the sample mean difference, f$ar{X_{1}}-ar{X_{2}}f$  is:

 

 

 A.normally distributed

 

 B.approximately normal

 

 C.chi-squared distributed with 99 degrees of freedom

 

 D.t - distributed with 98 degrees of freedom

 

 

Question 7 of 23

1.0 Points

Multiple myeloma or blood plasma cancer is characterized by increased blood vessel formulation in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient’s own stem cells. The following data represent the bone marrow microvessel density for a sample of 7 patients who had a complete response to a stem cell transplant as measured by blood and urine tests. Two measurements were taken: the first immediately prior to the stem cell transplant, and the second at the time of the complete response. 

 

Patient

1

2

3

4

5

6

7

Before

158

189

202

353

416

426

441

After

284

214

101

227

290

176

290


Perform an appropriate test of hypothesis to determine if there is evidence, at the .05 level of significance, to support the claim that the mean bone marrow microvessel density is higher before the stem cell transplant than after the stem cell transplant? What is the value of the sample test statistic?

 

 

 A.t = 2.7234

 

 B.p = 2.7234

 

 C.z = 1.8424

 

 D.t = 1.8424

 

 

Question 8 of 23

1.0 Points

A type I error occurs when the:

 

 

 A.null hypothesis is incorrectly accepted when it is false

 

 B.null hypothesis is incorrectly rejected when it is true

 

 C.test is biased

 

 D.sample mean differs from the population mean

 

Question 9 of 23

1.0 Points

You conduct a hypothesis test and you observe values for the sample mean and sample standard deviation when n = 25 that do not lead to the rejection of H0. You calculate a p-value of 0.0667. What will happen to the p-value if you observe the same sample mean and standard deviation for a sample size larger than 25?

 

 

 A.The p – value decreases

 

 B.The p – value increases

 

 C.The p – value stays the same

 

 D.The p – value may increase or decrease

 

 

Question 10 of 23

1.0 Points

The null and alternative hypotheses divide all possibilities into:

 

 

 A.two sets that overlap

 

 B.two sets that may or may not overlap

 

 C.two non-overlapping sets

 

 D.as many sets as necessary to cover all possibilities

 

 

 

Question 11 of 23

1.0 Points

The t- distribution for developing a confidence interval for a mean has _____ degrees of freedom.

 

 

 A.n - 1

 

 B.n - 2

 

 C.n + 1

 

 D.n

 

Question 12 of 23

1.0 Points

A sample of 25 different payroll departments found that the employees worked an average of 310.3 days a year with a standard deviation of 23.8 days. What is the 90% confidence interval for the average days worked by employees in all payroll departments?

 

 

 A.301.0 < \f$\mu \f$ < 319.6

 

 B.298.0 < \f$\mu \f$ < 322.6

 

 C.302.2 < \f$\mu \f$ < 318.4

 

 D.314.1 < \f$\mu \f$ < 316.8

 

Question 13 of 23

1.0 Points

Given that Z is a standard normal random variable, P(-1.0 < Z < 1.5) is

 

 

 A.0.9332

 

 B.0.0919

 

 C.0.8413

 

 D.0.7745

 

 

Question 14 of 23

1.0 Points

In a small town, 60% of the households have dogs. If 5 households are randomly selected, what is the probability that at least 4 of them have dogs?

 

 

 A.0.337

 

 B.0.8

 

 C.3

 

 D.0.259

 

Question 15 of 23

1.0 Points

The number of ways to choose two representatives from a committee of 13 people is

 

 

 A.55

 

 B.13!

 

 C.156

 

 D.78

 

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 sport preference poll yielded the following data for men and women. Use a 5% significance level and test to determine if sport preference and gender are independent.

Sport Preferences of Men and Women

 

Basketball

Football

Soccer

 

Men

20

25

30

75

Women

18

12

15

45

 

38

37

45

120



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.  There 
is sufficient evidence to support the claim that one's sport preference is dependent on one's gender.
2. There is not sufficient evidence to support the claim that one's sport preference is dependent on one's gender.

Answer:     Enter only a 1 or 2 for your answer.

 

 

 

 

Question 17 of 23

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 marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). A random sample of 12 equal –sized stores is selected, with the following results:

 

Store

Shelf Space(X)

Weekly Sales(Y)

1

10

2.0

2

10

2.6

3

10

1.8

4

15

2.3

5

15

2.8

6

15

3.0

7

20

2.7

8

20

3.1

9

20

3.2

10

25

3.0

11

25

3.3

12

25

3.5

 
 

 

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. 

Two teams of workers assemble automobile engines at a manufacturing plant in Michigan. A random sample of 145 assemblies from team 1 shows 15 unacceptable assemblies. A similar random sample of 125 assemblies from team 2 shows 8 unacceptable assemblies. 

If you are interested in determining if there is sufficient evidence to conclude, at the 10% significance level, that the two teams differ with respect to their proportions of unacceptable assemblies, what is/are the critical value you would use to conduct such a test of hypothesis? 

Place your answer, rounded to 2 decimal places, in the blank. If there are two critical values, place only the positive value in the blank. For example, 2.34 would be a legitimate entry.  

 

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. 

Scores on a mathematics examination appear to follow a normal distribution with mean of 65 and standard deviation of 15. The instructor wishes to give a grade of “C” to students scoring between the 60th and 70th percentiles on the exam. 

What score represents the 70th percentile score on the mathematics exam? Place your answer in the blank, rounded to a whole number. For example, 62 would be a legitimate entry.  

 

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. 

If a sample has 25 observations and a 99% confidence estimate for f$mu f$   is needed, the appropriate value of the t-multiple required is  .  Place your answer, rounded to 3 decimal places, in the blank. For example, 3.456 would be an appropriate 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. 

In February 2002 the Argentine peso lost 70% of its value compared to the United States dollar. This devaluation drastically raised the price of imported products. According to a survey conducted by AC Nielsen in April 2002, 68% of the consumers in Argentina were buying fewer products than before the devaluation, 24% were buying the same number of products, and 8% were buying more products. Furthermore, in a trend toward purchasing less-expensive brands, 88% indicated that they had changed the brands they purchased. Suppose the following complete set of results were reported. Use the following data to answer this question.  

 

 

Number of Products Purchased

 

Brands Purchased

Fewer

Same

More

Total

Same

10

14

24

48

Changed

262

82

8

352

Total

272

96

32

400

 
What is the probability that a consumer selected at random purchased fewer products than before? Place your answer, rounded to 4 decimal places, in the blank. 

 

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 ABC battery company claims that their batteries last 100 hours, on average. You decide to conduct a test to see if the company's claim is true. You believe that the mean life may be different from the 100 hours the company claims. You decide to collect data on the average battery life (in hours) of a random sample of n = 20 batteries. Some of the information related to the hypothesis test is presented  below. 

Test of H0f$mu f$ = 100 versus H1f$mu 
eq f$   100 
Sample mean 98.5 
Std error of mean 0.777 

Assuming the life length of batteries is normally distributed, what is the p-value associated with this test?  Place your answer, rounded to 3 decimal places in the blank. For example, 0.234 would be a legitimate entry. 

 

 

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. 

An ice cream vendor sells three flavors: chocolate, strawberry, and vanilla. Forty five percent of the sales are chocolate, while 30% are strawberry, with the rest vanilla flavored. Sales are by the cone or the cup. The percentages of cones sales for chocolate, strawberry, and vanilla, are 75%, 60%, and 40%, respectively. For a randomly selected sale, define the following events:

f$A_{1}f$  = chocolate chosen

f$A_{2}f$  = strawberry chosen

f$A_{3}f$  = vanilla chosen

f$Bf$  = ice cream on a cone

f$ar{B}=f$ ice cream in a cup

Find the probability that the ice cream was strawberry flavor, given that it was sold in a cup. Placeyour answer, rounded to 4 decimal places, in the blank. For exampe, 0.3456 would be a legitimate entry. 

 
 
 
 
 
 
 
 

 

Subject Mathematics
Due By (Pacific Time) 08/18/2013 05:30 pm
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