Need some help with these 2:

1)

Verify that the following function is a probability mass function, and determine the requested probabilities. [Give exact answers in form of fraction.] f(x) = (3f4)(1i4)I, x = 0,12,... Actual lengths of stay at a hospital's emergency department in 2009 are shown in the fol lowing table (rounded to the nearest hour). Length of stay is the total of wait and service times. Some longer stays are also approximated as 15 hours in this table. Hours Count Percent 1 16 3.20 2 54 10.80 3 84 16.80 4 100 20.00 5 83 16.60 6 69 13.80 7 42 8.40 8 11 2.20 9 16 3.20 10 15 3.00 15 10 2.00 Determine the cumulative distribution function for the random variable.