An engineer wants to know if producing metal bars using a new experimental treatment rather than the conventional treatment makes a difference in the tensile strength of the bars. At a=0.01, answer parts (a) through (e). Assume the population variances are equal and the samples are random.

treatment Tensile Strengths

experimental 365 390 396 427 389 369 374

conventional 357 397 447 422 406 375 393 434 407 378

(a) Identify the claim and state Ho and Ha

The claim is, The new treatment _________ in a tensile strength of bars

The null hypothesis, Ho is _____. The alternative hypothesis Ha is ___________

Which hypothesis is the claim?

A. The alternative hypothesis Ha

B. The null hypothesis Ho

(b) Find the critical value(s) and identify the rejection region(s). Enter the critical value(s)_______ round to three decimal places as needed.

Select the correct rejection region(s) below.

A. t < -to, t > to

B. -to < t < to

C. t > to

D. t < -to

(c) Find the standardized test statistic. t= _____? (round to nearest thousand)

(d) Decide whether to reject or fail to reject the null hypothesis?

A. Fail to reject

B. Reject

(e) Interpret the decision in the context of the original claim. At the 1% significance level ___________ enough evidence to support the claim.