A random group of thirty customers at a local theater was in
A random group of thirty customers at a local theater was interviewed regarding their movie viewing
habits. The following responses were obtained for
the question, “How many times during the past
month did you go to the movies?”
Number of movies attended
0
1
2
3
4
Number of customers
3
10
8
6
3
a.
Construct the probability distribution for X = number of times to attend a movie during the
past
month and construct the cumulative probability distribution for this data.
b.
Find the probability that a customer selected at random went to the movies: 1) more than one
time, 2) two times, 3) at least two times, 4) no more than three times.
c.
Compute t
he mean, variance, and standard deviation for this data.
Solution
E(X) = Mean = 7.267
E(X^2) = 59.4
Var(x) = 6.596
Std dev = 2.568
| No of customers | Prob | Cum prob | x*p | x^2*p | |
| 3 | 0 | 0.1 | 0.1 | 0.3 | 0.9 |
| 10 | 10 | 0.333333 | 0.433333 | 3.333333 | 33.33333 |
| 8 | 16 | 0.266667 | 0.7 | 2.133333 | 17.06667 |
| 6 | 18 | 0.2 | 0.9 | 1.2 | 7.2 |
| 3 | 12 | 0.1 | 1 | 0.3 | 0.9 |
| 30 | 56 | 1 | 7.266667 | 59.4 |

