What hypothesis testing procedure should you use to answer these questions? 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 nondefective. An improvement in the process is being considered that they feel will raise the proportion of nondefectives above the current 90%, but costs a considerable amount. A sample of 121 items are produced with the new process and 7 are defective. Is this evidence sufficient (at α = 0.05) to conclude that the method has been improved?
Question 24 options:
One sample z-test for the population mean.
Two sample z-test for the population means.
One sample z-test for proportions.
Two sample z-test for proportions.
One sample t-test for the population mean.
None of our hypothesis tests fit.