Question

answer neatly and correctly please!

The breaking strengths of cables produced by a certain manufacturer have a mean, u, of 1850 pounds, and a standard deviation of 55 pounds. It is claimed that an improvement in the manufacturing process has increased the mean breaking strength. To evaluate this claim, 70 newly manufactured cables are randomly chosen and tested, and their mean breaking strength is found to be 1868 pounds. Can we support, at the 0.01 level of significance, the claim that the mean breaking strength has increased? (Assume that the standard deviation has not changed.) Perform a one-tailed test. Then fill in the table below. Carry your intermediate computations to at least three decimal places, and round your responses as specified in the table. The null hypothesis: The alternative hypothesis: H : 7 s . O=D Oso 020 0+0 <D O>o X 5 ? The type of test statistic: (Choose one) The value of the test statistic: (Round to at least three decimal places.) The p-value: (Round to at least three decimal places.) Can we support the claim that the mean breaking strength has increased? Yes No

Answer 1

Below are the null and alternative Hypothesis,
Null Hypothesis: μ = 1850
Alternative Hypothesis: μ > 1850

Test statistic,
z = (xbar - mu)/(sigma/sqrt(n))
z = (1868 - 1850)/(55/sqrt(70))
z = 2.738

P-value Approach
P-value = 0.003
As P-value < 0.01, reject the null hypothesis.

Yes, we can conclude that mean breaking time strength has increased.