Refer to the Scheer Industries example in Section 8.2. Use 6.86 days as a planning value for the population standard deviation. a. Assuming 95% confidence, what sample size would be required to obtain a margin of error of 1.5 days (round up to the next whole number)? b. Assuming 90% confidence, what sample size would be required to obtain a margin of error of 2.5 days (round up to the next whole number)