In: Statistics and Probability
In a study of store checkout scanners, a sample of 1234 items were checked and 20 of them were overcharges. It had been claimed by the manufacturers that only 2% of the sales would be overcharges. Based on these results, at the 1% level of significance, do the scanners appear to overcharge less often than the 2%?
(1) List all the information necessary for conducting the hypothesis test and state which
test you are doing.
(2) State the null and alternative hypotheses and whether you would use a right-tailed
test, a left-tailed test, or a two-tailed test.
(3) Sketch the critical reason, indicating on the sketch what the critical value(s) are.
(4) Determine the calculated z or t.
(6) Decide if you will Reject or Fail to Reject the Null Hypothesis.
(7) Interpret your conclusion in terms of the problem.
The detailed working out of the hypothesis test is given below
conclusion : There is no sufficient evidence to support the claim that the scanners appear to overcharge less often than the 2%