[Solution Library] As reported by the Motor Vehicle Manufacturers Association of the United States in Motor Vehicle Facts and Figures, the number of cars
Question: As reported by the Motor Vehicle Manufacturers Association of the United States in Motor Vehicle Facts and Figures, the number of cars and trucks in the use by age are as shown in the following contingency table. Frequencies are in millions.
We are interested in testing the following null and alternative hypotheses:
From the table above we compute the table with the expected values
| Expected | Junior | Senior | Soph |
| F | 5.2 | 1.6 | 3.2 |
| M | 7.8 | 2.4 | 4.8 |
The way those expected frequencies are calculated is shown below:
Finally, we use the formula
to get
| (fo - fe)²/fe | Junior | Senior | Soph |
| F | 0.0077 | 1.225 | 0.45 |
| M | 0.0051 | 0.8167 | 0.3 |
The calculations required are shown below:
Hence, the value of Chi-Square statistics is
The critical Chi-Square value for
and
degrees of freedom is
. Since
<
, then we fail to reject the null hypothesis, which means that we don't have enough evidence to reject the null hypothesis of independence.
| Age | Car | Truck | Total |
| Under 6 | 46.2 | 27.8 | 74.0 |
| 6-8 | 26.9 | 40.0 | |
| 9-11 | 23.3 | 10.7 | |
| 12 & Ov er | 26.8 | 18.6 | 45.4 |
| Total | 1 23.2 |
- How many cells does this contingency table have?
- Fill in the missing entries
- What is the total number of cars and trucks in use?
- How many vehicles are trucks?
- How many vehicles are between 6 and 8 years old?
- How many vehicles are trucks that are between 9 and 11 years old?
Deliverable: Word Document 