Suppose that the quality control manager for a cereal manufacturer wants to ensure that bags of cereal are being filled correctly. The equipment is calibrated to fill bags with a mean of 24 oz of cereal with a standard deviation of 0.3 oz. The quality control inspector selects a random sample of 60 boxes and finds that the mean amount of cereal for these boxes is 23.94 oz. ereal manufacturer wants to ensure that bags of cereal are being filled correctly. The equipment is calibrated to fill bags with a mean of 24 oz of cereal with a standard deviation of 0.3 oz. The quality control inspector selects a random sample of 60 boxes and finds that the mean amount of cereal for these boxes is 23.94 oz. He uses this data to conduct a one-sample z ‑test with a null hypothesis of H 0 : μ = 24 against the alternative hypothesis H 1 : μ ≠ 24 , where μ is the mean amount of cereal in each box. He calculates a z ‑score of − 1.55 and a P -value of 0.1211 .

Are these results statistically significant at a significance level of 0.05?