In: Statistics and Probability
The parking authority in downtown Halifax reported the following information for a sample of 240 customers on the number of hours cars are parked and the amount they are charged: Number of Hours Frequency Amount Charged 1 23 $2 2 41 4 3 54 6 4 41 8 5 38 10 6 11 14 7 6 18 8 26 20 Total 240 a-1. Convert the information on the number of hours parked to a probability distribution. (Round the final answers to 3 decimal places.) Hours Probability 1 2 3 4 5 6 7 8 a-2. Is this a discrete or a continuous probability distribution? b-1. Find the mean and the standard deviation of the number of hours parked. (Round the final answers to 3 decimal places.) Mean Standard deviation b-2. How would you answer the question, how long is a typical customer parked? (Round the final answer to 3 decimal places.) The typical customer is parked for hours. c. Find the mean and standard deviation of the amount charged. (Round the final answers to 2 decimal places.) Mean Standard deviation
Number of hours | Frequency | Amount charged |
1 | 23 | 2 |
2 | 41 | 4 |
3 | 54 | 6 |
4 | 41 | 8 |
5 | 38 | 10 |
6 | 11 | 14 |
7 | 6 | 18 |
8 | 26 | 20 |
240 |
a)
Number of hours | p |
1 | 0.095833 |
2 | 0.170833 |
3 | 0.225 |
4 | 0.170833 |
5 | 0.158333 |
6 | 0.045833 |
7 | 0.025 |
8 | 0.108333 |
this is discrete
b)
Number of hours | p | xp | x^2p |
1 | 0.0958 | 0.0958 | 0.0958 |
2 | 0.1708 | 0.3417 | 0.6833 |
3 | 0.2250 | 0.6750 | 2.0250 |
4 | 0.1708 | 0.6833 | 2.7333 |
5 | 0.1583 | 0.7917 | 3.9583 |
6 | 0.0458 | 0.2750 | 1.6500 |
7 | 0.0250 | 0.1750 | 1.2250 |
8 | 0.1083 | 0.8667 | 6.9333 |
1.0000 | 3.9042 | 19.3042 |
mean = 3.904
sd =sqrt(E(X^2) - (E(X))^2)
=sqrt(19.3042 -3.9042^2)
= 2.01529
=2.015
b-2)
typical number of hours = mean = 3.904
c)
Amount charged | p | xp | x^2p |
2 | 0.0958 | 0.1917 | 0.3833 |
4 | 0.1708 | 0.6833 | 2.7333 |
6 | 0.2250 | 1.3500 | 8.1000 |
8 | 0.1708 | 1.3667 | 10.9333 |
10 | 0.1583 | 1.5833 | 15.8333 |
14 | 0.0458 | 0.6417 | 8.9833 |
18 | 0.0250 | 0.4500 | 8.1000 |
20 | 0.1083 | 2.1667 | 43.3333 |
1.0000 | 8.4333 | 98.4000 |
mean = 8.433
sd = sqrt(98.4 - 8.4333^2)
= 5.223
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