1. A certain prescription medicine is supposed to contain an average of 250 parts per million (ppm) of a certain chemical. If the concentration is higher than this, the drug may cause harmful side effects; if it is lower, the drug may be ineffective. The manufacturer runs a check to see if the mean concentration conforms to the target level of 250 ppm or not. A simple random sample of 100 portions is tested, and the sample mean concentration is found to be 246 ppm with a sample standard deviation of 12 ppm. Test at 1 percent level. The claims: Ho: Ha: a = The calculation. z or t by formula: p value by calculator: The comparison: z-score: P-value: The narrative