In: Statistics and Probability
1. In a study of vehicle ownership, it has been found that 30%
of U.S. households do not own a vehicle, with 46% owning 1 vehicle,
and the remaining owning 2 or more vehicles. The data for a random
sample of 192 households in a resort community are as
follows:
57 owned 0 vehicles, 104 owned 1 vehicle, and the remaining owned 2
or more vehicles.
When testing (at the 5% level of significance) whether the
vehicle-ownership distribution in this community differs from that
of the nation as a whole what is the test statistic? (please round
your answer to 3 decimal places)
2. When testing (at the 5% level of significance) whether the
vehicle-ownership distribution in this community differs from that
of the nation as a whole what is the test statistic? (please round
your answer to 3 decimal places)
In a study of vehicle ownership, it has been found that 29% of
U.S. households do not own a vehicle, with 45% owning 1 vehicle,
and the remaining owning 2 or more vehicles. The data for a random
sample of 203 households in a resort community are as
follows:
77 owned 0 vehicles, 106 owned 1 vehicle, and the remaining owned 2
or more vehicles.
When testing (at the 10% level of significance) whether the
vehicle-ownership distribution in this community differs from that
of the nation as a whole what is the critical value? (please round
your answer to 3 decimal places)
Que.1
We use chi-square test to the following hypothesis:
Hypothesis:
H0 : The vehicle-ownership distribution in this community same as that of the nation.
Ha : The vehicle-ownership distribution in this community differs from that of the nation.
Observation table:
No. of vehicle | Pi | Observed freq (Oi) | Expected Freq (Ei) = Npi | (Oi - Ei)2/Ei |
0 | 0.3 | 57 | 57.6 | 0.00625 |
1 | 0.46 | 104 | 88.32 | 2.78376812 |
2 or more | 0.24 | 31 | 46.08 | 4.93503472 |
192 | 7.72505284 |
Test statistic,
Where,
n = Total number of observations
s = number of parameter estimated
k= number of degrees of freedom lost due to pooling
Hence degrees of freedom = n-s-k-1 = 3 - 0-0-1 = 2
Critical value = 5.99
Since calculated value of chi-square is greater than critical value we reject null hypothesis and conclude that the vehicle-ownership distribution in this community differs from that of the nation at 5% level of significance.
Que.2
Hypothesis:
H0 : The vehicle-ownership distribution in this community same as that of the nation.
Ha : The vehicle-ownership distribution in this community differs from that of the nation.
Observation table:
No. of vehicle | Pi | Observed freq (Oi) | Expected Freq (Ei) = Npi | (Oi - Ei)2/Ei |
0 | 0.29 | 77 | 58.87 | 5.58343639 |
1 | 0.45 | 106 | 91.35 | 2.34945265 |
2 | 0.26 | 20 | 52.78 | 20.3586283 |
203 | 28.2915173 |
Where,
n = Total number of observations
s = number of parameter estimated
k= number of degrees of freedom lost due to pooling
Hence degrees of freedom = n-s-k-1 = 3 - 0-0-1 = 2
Critical value = 5.99
Since calculated value of chi-square is greater than critical value we reject null hypothesis and conclude that the vehicle-ownership distribution in this community differs from that of the nation at 5% level of significance.
Critical value at 10% level of significance = 4.605
Since calculated value of chi-square is greater than critical value we reject null hypothesis and conclude that the vehicle-ownership distribution in this community differs from that of the nation at 10% level of significance.