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The 90% confidence interval estimate for a population standard deviation when a

ID: 3129861 • Letter: T

Question

The 90% confidence interval estimate for a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items is

Select one:

A. 4.18 to 15.07

B. 5.18 to 11.15

C. 5.44 to 10.32

D. 29.55 to 106.53

Question 8

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A major automobile manufacturer claimed that the frequencies of repairs on all five models of its cars are the same. A sample of 200 repair services showed the following frequencies on the various makes of cars.

Select one:

A. 4.250

B. 7.882

C. 9.488

D. 11.234

E. None of the above answers is correct

Question 9

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Select one:

A. should be rejected

B. should not be rejected

C. should be revised

D. None of these alternatives is correct.

Question 10

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Select one:

A. do not reject Ho

B. reject Ho

C. don not reject Ha

D. None of the above answers is correct

Question 11

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An insurance company has gathered the following information regarding the number of accidents reported per day over a period of 100 days.

Select one:

A. distribution is Poisson

B. distribution is not Poisson

C. distribution is normal

D. distribution is not normal

E. None of the above answers is correct

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It is crucial that the variance of a production process be less than or equal to 25. A sample of 22 is taken. The sample variance equaled 26. Construct a 90% confidence interval for the population standard deviation.

Select one:

A. 17.432 to 48.1038

B. 4.3451 to 6.0728

C. 16.7123 to 47.1043

D. 4.0881 to 6.8633

E. None of the above answers is correct

Question 13

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We want to test the hypothesis that the population variances are equal. Refer to above data. The test statistic for this problem equals

Select one:

A. .67

B. .84

C. 1.19

D. 1.50

NEED HELP WITH THIS ASAP PLEASE!

Model of Car Frequency A 32 B 45 C 43 D 34 E 46

Explanation / Answer

multiple questions . first 4 questions answered

The 90% confidence interval estimate for a population standard deviation when a sample variance of 50 is obtained from a sample of 15 items is

Select one:

A. 4.18 to 15.07

B. 5.18 to 11.15

C. 5.44 to 10.32

D. 29.55 to 106.53

Confidence Interval Estimate for the Population Variance

Data

Sample Size

15

Sample Standard Deviation

7.0710678

Confidence Level

90%

Intermediate Calculations

Degrees of Freedom

14

Sum of Squares

699.999998

Single Tail Area

0.05

Lower Chi-Square Value

6.5706

Upper Chi-Square Value

23.6848

Results

Interval Lower Limit for Variance

29.5548

Interval Upper Limit for Variance

106.5347

Interval Lower Limit for Standard Deviation

5.44

Interval Upper Limit for Standard Deviation

10.32

Question 8

Question text

A major automobile manufacturer claimed that the frequencies of repairs on all five models of its cars are the same. A sample of 200 repair services showed the following frequencies on the various makes of cars.

Model of Car

Frequency

A

32

B

45

C

43

D

34

E

46


At  = 0.05, test the manufacturer's claim. What is the critical value of the test statistic?

Select one:

A. 4.250

B. 7.882

C. 9.488

D. 11.234

E. None of the above answers is correct

Question 9

n = 23 S2 = 60 H0:2  66 Ha: 2 < 66 . What statement should be made about the null hypothesis if significance level is 5%?

Select one:

A. should be rejected

B. should not be rejected

C. should be revised

D. None of these alternatives is correct.

Calculated chi square =20 > 12.34 table value at 5% level.

Question 10

A sample of 61 items provided a sample mean of 932, a sample mode of 900, and a sample standard deviation of 11. Test the following hypotheses using  = 0.05. What is your conclusion? H0: 2  80 Ha: 2 > 80

Select one:

A. do not reject Ho

B. reject Ho

C. don not reject Ha

D. None of the above answers is correct

Chi-Square Test of Variance

Data

Null Hypothesis                        s^2=

80

Level of Significance

0.05

Sample Size

61

Sample Standard Deviation

11

Intermediate Calculations

Degrees of Freedom

60

Half Area

0.025

Chi-Square Statistic

90.7500

Upper-Tail Test

Upper Critical Value

79.0819

p-Value

0.0063

Reject the null hypothesis

Confidence Interval Estimate for the Population Variance

Data

Sample Size

15

Sample Standard Deviation

7.0710678

Confidence Level

90%

Intermediate Calculations

Degrees of Freedom

14

Sum of Squares

699.999998

Single Tail Area

0.05

Lower Chi-Square Value

6.5706

Upper Chi-Square Value

23.6848

Results

Interval Lower Limit for Variance

29.5548

Interval Upper Limit for Variance

106.5347

Interval Lower Limit for Standard Deviation

5.44

Interval Upper Limit for Standard Deviation

10.32