A certain allergy medicine company is supposed to contain an average of 245 ppm, if higher than 245ppm the drug will cause side effects and if the concentration is below 245ppm will be ineffective. want to check the mean concentration of a shipment is of the 245ppm or not. a sample of 24 portions were tested and found the sample mean is 250 ppm with standard deviation of 12ppm. Test .05 alpha level of concentration to see if in desired level