. Let X have a normal distribution with mean 0 and variance 2. Compute . Ann takes two tests. On the rst test, she scores 74/100 (74%) and on the second, 98/120 (82%). Test scores are normally distributed; on the rst test with mean 66 and standard deviation 4, and on the second test with mean 90 and standard deviation 5. Which is her better test result? . A new residential area which is to include a parking garage is planned. There will be room for 200 families and the number of cars per family has mean 0.8 and standard deviation 0.6. (a) Find the mean and standard deviation of the total number of cars. (b) If the garage has 1'70 parking spots, nd the (approximate) prob ability that there will be room for all cars. (c) To be at least 99% certain that there will be room for all cars, how many spots should the garage have? (d) To be at least 100q% certain, how many spots should the garage have? Give the answer expressed with the probability q and the inverse (131 of (I)