The data set below represents a sample of scores on a 10-point quiz. 7, 4, 9, 6, 10, 9, 5, 4 1 Find the sum of the mean and the median. 14.25 12.75 12.25 15.50 13.25 In a certain state, 36% of adults drive every day. Suppose a random sample of 625 adults from the state is chosen. Let X denote the number in the sample who drive every day. Find the value of X that is two standard deviations above the mean. 237 513 249 201 225 Lifetimes of batteries of a certain type are normally distributed with mean 42.6 hours and standard deviation 2.8 hours. Find the lifetime in hours that would separate the 7.5% of batteries with the shortest lifetimes from the rest. 38.57 40.50 45.80 42.39 35.80 Find the number of US adults that must be included in a poll in order to estimate, with margin of error 1.5%, the percentage that are concerned about high gas prices. Use a 94% confidence level, and assume about 79% are concerned about gas prices. 2607 2259 1387 603 3928