1. To assess the accuracy of laboratory scale, a standard weight known to weigh 10 grams is weighed repeatedly. The weight is weighed 40 times. The mean result is 10.230 grams. The standard deviation of the scale readings is 0.020 gram. (a) Give a 98% confidence interval for the mean of repeated measurements of the weight. Round your answers to three decimal places. (b) How many measurements must be averaged to get a margin of error of .001 with 98% confidence?

2. A Gallup Poll asked a sample of Canadian adults if they thought the law should allow doctors to end the life of a patient who is in great pain and near death if the patient makes a request in writing. The poll included 270 people in Quebec, 221 of whom agreed that doctorassisted suicide should be allowed. (a) Construct 95% confidence interval for the proportion of all Quebec adults who would allow doctor-assisted suicide? Round your answers to three decimal places. (b) How large a sample is needed to get the common 3 percentage point margin of error with the same 95% confidence level?

3. A group of physical education majors was discussing the heights of female runners and whether female runners tended to be tall, on the average. They decided to estimate the mean height of female runners. A sample of 12 runners showed a sample mean height of 65.80 inches and a sample standard deviation of 1.95 inches. Assume the population is approximately normal. Find a 90% confidence interval for the mean ???? of the population of female runners from which the 12 runners were selected.