To assess the accuracy of a laboratory scale, a standard weight known to weigh 10 grams is weighed repeatedly. The scale readings are normally distributed with unknown mean (this mean is10 gramsif the scale has no bias). The standard deviation of the scale readings is known to be0.0006gram.

(a) The weight is measuredfivetimes. The mean result is 10.0023 grams. Give a 98% confidence interval for the mean of repeated measurements of the weight. (Round your answers to four decimal places.) (______,_____)

(b) How many measurements must be averaged to get a margin of error of0.0001 with 98% confidence? (Round your answer up to the nearest whole number.)