The percentage of people (to the nearest 10) responding to an advertisement is a random variable with the following probability distribution:
|
X(%)
|
P(x)
|
|
0
|
0.10
|
|
10
|
0.20
|
|
20
|
0.35
|
|
30
|
0.20
|
|
40
|
0.10
|
|
50
|
0.05
|
a. Show that P(x) is a probability distribution.
b. Find the cumulative distribution function.
c. Find the probability that more than 20% will respond to the ad.