Question

What hypothesis tes!ng procedure should you use to answer these ques!ons? Assume all samples are simple random samples, and assume α = 0.05 if it isn’t specified. A manufacturing company claims that 90% of items produced by a certain process are nondefec!ve. An improvement in the process is being considered that they feel will raise the propor!on of nondefec!ves above the current 90%, but costs a considerable amount. A sample of 121 items are produced with the new process and 7 are defec!ve. Is this evidence sufficient (at α = 0.05) to conclude that the method has been improved?

One sample z-test for the popula!on mean.

Two sample z-test for the popula!on means.

One sample z-test for propor!ons.

Two sample z-test for propor!ons.

One sample t-test for the popula!on mean.

None of our hypothesis tests fit.

Answer 1

One sample z-test for proportions.

Z test statistic for proportion

2P-p