Must show all your work step by step in order to receive full credit; Excel is not allowed 1. Use the given information below to answer the below given questions : X f 1 1 2 0 a. Range b. Variance c. Standard deviation 2. The mean income of a group of sample observations is $250; the standard deviation is $20. According to Chebyhev's theorem, at least what percent of the incomes will lie between $200 and $300? 3. A sample of the monthly amounts spent for food by families of four receiving food stamps approximates a symmetrical, bell-shaped frequency distribution. The sample mean is $200; the standard deviation is $25. a. About 76 percent of the monthly food expenditures are between what two amounts? b. About 90 percent of the monthly food expenditures are between what two amounts? a. b