DESPERATE for Stats homework help (10 points for best answer)!?

The supervisor of a production line believes that the average time to assemble an electronic component is 17 minutes. Assume that assembly time is normally distributed with a standard deviation of 3.8 minutes. The supervisor times the assembly of 20 components, and finds that the average time for completion was 17.85 minutes. Is there evidence that the average amount of time required to assemble a component is something other than 17 minutes?

We should reject at 9% level of significance if 

 test-statistic < -1.341 

 test-statistic > 1.392 

 | test-statistic | > 1.341 

 | test-statistic | > 1.695 

If α= 0.09, what will be your conclusion? 

not enough information to reach a decision 

Do not reject H0 

Reject H0 

The p-value of the test is equal to

 

0.8414 

0.1586 

0.3171 

Please show work/explain so I can understand this for my exam. THANK YOU!

1 Answer

Relevance
  • Alan
    Lv 7
    3 weeks ago

    Since you say different, 

    the 9 % alpha 

    mean from  alpha/2 to 1 - alpha/2 

    4.5 % to  95.5  leaving 91 % in the middle 

    so find P(z< Z) = 0.955 

    P(z<1.69) = .95449

     P(z< 1.70) = 0.95543 

    so it is between 1.69 and 1.70 

    so reject it must least than -1.69 or greater than 1.69  

    so the correct answer is 

     | test-statistic | > 1.695

    so for X = 17.85  

    Z =    (x-mean)/ (standard deviation/sqrt(N)  

    Z = (17.85-17) /  (3.8/sqrt(20))

    Z = 0.85/ 0.8497058314 =  1.0003462005

    since 1.0003 < 1.695 , you cannot reject the NULL Hypothesis 

    answer 2: 

    Do not reject H0 

    P(z<1.00)  read from the z-table =  0.84134  

    from this z-table 

    https://www.math.arizona.edu/~rsims/ma464/standard...

    so from your answers 

    0.8414 

Still have questions? Get your answers by asking now.