What price do farmers get for their watermelon crops? In the third week of July, a random sample of 42 farming regions gave a sample mean ofx = $6.88 per 100 pounds of watermelon. Assume that o is known to be $1.92 per 100 pounds. (a) Find a 90% condence interval for the population mean price {per 100 pounds) that farmers in this region get for their watermelon crop. What is the margin of error? (Round your answers to two decimal places.) lower limit $ X upper limit 39 149.9 x margin of error $ X (in) Find the sample size necessary for a 90% confidence level with maximal error of estimate E = 0.41 for the mean price per 100 pounds of watermelon. (Round up to the nearest whole number.) S farming regions (c) A farm brings 15 tons of watermelon to market. Find a 90% confidence interval for the population mean cash value of this crop. What is the margin of error? Hint: 1 ton is 2000 pounds. (Round your answers to two decimal places.) lower limit is :J upper limit $ S margin of error $ [:]