On the basis of extensive tests, the yield point of a particular type of mild st

Question

On the basis of extensive tests, the yield point of a particular type of mild steel- reinforcing bar is known to be normally distributed with historical standard deviation 100. A sample of 35 bars was taken and has a sample mean of 8439 lbs Suppose that the specifications are that the yield point of a particular type of mild steel-reinforcing bar should be 8475 lbs. (a) In performing one-sample hypothesis tests, would we use z* or t* in this situation? Briefly explain why you would use one instead of the other. (b) Is there sufficient evidence that the mean yield point is less than the specifications call for (the specs say 8475)? Conduct a hypothesis test (c) State the kind of error could have been made in context of the problem.

Explanation / Answer

Given the details

Stadand Deviation= 100

N:-Sample Size= 35

Samle Mean= 8439 lbs( Pounds)

A> We should perform Z test instead of T Test

Reasons:- We know the populaion Standard Deviation which os 100lbs and the number of Observations for sample mean is > 30

B> . Hypothesis test At 95% confidence level

H0:- Mu0<= 8475( Specs)

HA:- Mu0> 8475

Performing the Z test

z test= (Mu0- X)/ (Population Standard deviation/ Sqrt (N))

The Z value obtained= -2.129

So P value= .9834

So we fail to reject the null hypothesis

C> The possible kind of error that could have been made in the context of the problem

Type 1 Error that is to reject nul;l hypothesis.

Related Questions

Navigate

• Browse (All)
• Browse O
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.