Please explain

Part 2 of 3 V (b) Following is a dotplot of these data. Is it reasonable to assume that the population is approximately normal? 100 150 200 250 300 350 400 It is reasonable to assume that the population is approximately normal. Part: 2 / 3 Part 3 of 3 (c) If appropriate, construct a 99.5% confidence interval for the mean price for all phones of this type being sold on the Internet in 2013. Round your intermediate step to three decimal places. Round your answer to one decimal place. A 99.5% confidence interval for the mean price for all phones of this type being sold on the Internet in 2013 is