Question

A manufacturing company claims that the mean breaking strength of the cables supplied s 1500 with a standard deviation of 100.A sample of size 9 cables tested is having mean breaking strength of 1600 with a standard deviation of 30. If the distribution of the mean breaking strength is normal, does this support the claim at 1% level of significance

Answer 1

Answer:

Step-by-step explanation:

We need check the hypothesis

H0:Ц=1500 vs  Hₐ :Ц>1600

We use the z-test (n>30):

Z0=Ц−Ц0 / a/√n = 1530−1600/100/√30  ≈ 0.127

Zcr = Z 0.99  = 2.33

Since Z 0 > Z cr then we reject H 0 and we conclude that a new technique can improve the break strength .

Answer :  we reject H 0and we conclude that a new techniquecan improve the break strength.