Problem 1 ( Confidence Interval Estimation with Known Variance). According to USA Today, customers are not settling for automobiles straight off the production lines. They typically get accessories that add a significant amount over the base sticker price. For BMW 3 Series with a sticker price of $40,250, the cost of accessories has an unknown mean and a known standard deviation = $3,450. A recent sample of 75 purchases yielded a sample mean of $8,200 above the sticker price as the cost of the accessories. (1.3) Moderate What sample size would be required to reduce the margin of error by 50% (i.e. to half of its current size)? (1.4) Challenging Based on the above sample of 75 purchases, a statistician calculates a confidence interval of 8200 400. What is the confidence level 1 associated with this interval.