The NJ Bureau of Employment gathered the following sample information on the number of hours unemployed workers spent looking for work last week. Hours Spent Searching Number of Unemployed 0 up to 20 12 20 up to 40 28 40 up to 60 60 60 up to 80 40 80 up to 100 20 (a) Determine the mean. (b) Determine the standard deviation.