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How strong a force (in pounds) is needed to pull apart pieces of wood 4 inches l

ID: 3231859 • Letter: H

Question

How strong a force (in pounds) is needed to pull apart pieces of wood 4 inches long and 1.5 inches square? The following are data from students performing a comparable laboratory exercise. Suppose that the strength of pieces of wood like these follow a Normal distribution with standard deviation 3000 pounds.

31,940             

  (a) We are interested in statistical significant evidence at the = 0.10 level for a claim that the mean is 32,500 pounds.                      

What are the null and alternative hypotheses?

H0: = 32,500
H1: 32,500

H0: = 32,500
H1: < 32,500   

H0: 32,500
H1: = 32,500

H0: = 32,500
H1: > 32,500

What is the value of the test statistic. (Round your answer to two decimal places.)

Z=

What is the P-value of the test? (Round your answer to four decimal places.)    

P-Value=

What is your conclusion?

There is enough evidence to conclude that the wood's mean strength differs from 32,500 pounds.

There is not enough evidence to conclude that the wood's mean strength differs from 32,500 pounds.

(b) We are interested in statistical significant evidence at the

= 0.10

H0: 31,500
Ha: = 31,500

H0: = 31,500
H1: 31,500    

H0: = 31,500
H1: < 31,500

H0: = 31,500
H1: > 31,500


What is the value of the test statistic. (Round your answer to two decimal places.)

Z=

What is the P-value of the test? (Round your answer to four decimal places

P-Value=

What is your conclusion?

There is enough evidence to conclude that the wood's mean strength differs from 31,500 pounds.

There is not enough evidence to conclude that the wood's mean strength differs from 31,500 pounds.

                                                                                                                                                                           

  

33,240     31,890     32,620     26,510     33,250     32,370     33,000     32,020     30,470     32,680     23,060     30,930     32,670     33,670     32,290     24,040     30,190     31,340     28,770    

31,940             

  (a) We are interested in statistical significant evidence at the = 0.10 level for a claim that the mean is 32,500 pounds.                      

What are the null and alternative hypotheses?

H0: = 32,500
H1: 32,500

H0: = 32,500
H1: < 32,500   

H0: 32,500
H1: = 32,500

H0: = 32,500
H1: > 32,500

What is the value of the test statistic. (Round your answer to two decimal places.)

Z=

What is the P-value of the test? (Round your answer to four decimal places.)    

P-Value=

What is your conclusion?

There is enough evidence to conclude that the wood's mean strength differs from 32,500 pounds.

There is not enough evidence to conclude that the wood's mean strength differs from 32,500 pounds.

(b) We are interested in statistical significant evidence at the

= 0.10

level for a claim that the mean is 31,500 pounds.

What are the null and alternative hypotheses?

H0: 31,500
Ha: = 31,500

H0: = 31,500
H1: 31,500    

H0: = 31,500
H1: < 31,500

H0: = 31,500
H1: > 31,500


What is the value of the test statistic. (Round your answer to two decimal places.)

Z=

What is the P-value of the test? (Round your answer to four decimal places

P-Value=

What is your conclusion?

There is enough evidence to conclude that the wood's mean strength differs from 31,500 pounds.

There is not enough evidence to conclude that the wood's mean strength differs from 31,500 pounds.

                                                                                                                                                                           

  

Explanation / Answer

a)H0: = 32,500
H1: 32,500

b)std error=std deviation/(n)1/2 =750

sample mean of above data=30797.5

hence test stat z=(X-mean)/std error =(30797.5-32500)/750=-2.27

c)pvalue =0.0232

There is enough evidence to conclude that the wood's mean strength differs from 32,500 pounds.

2nd)

H0: = 31,500
H1: 31,500

Z=(30797.5-31500)/750=-0.9367

p[ vlaue =0.3489

There is not enough evidence to conclude that the wood's mean strength differs from 31,500 pounds

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