Question

What is the average number of people that take the bus to work in New York and New Jersey?

Area | Frequency | Relative Frequency

NY | 295 | 0.75

NJ | 75 | 0.25

Build and interpret the confidence interval. Use these steps:

1. State the parameter of interest
2. Name the method
3. Verify the conditions (explaining the evidence that they are satisfied)
4. Perform the calculations
5. Interpret your Interval

Answer 1

The parameter of interest is the average number of people that take the bus to work.

The method used will be two-sample proportion test.

The 95% confidence interval for the difference in the average number of people that take the bus to work in New York and New Jersey is between 0.5367 and 0.6525.

We are 95% confident that the true difference in the average number of people that take the bus to work in New York and New Jersey is between 0.5367 and 0.6525.

p1	p2	pc
0.7973	0.2027	0.5	p (as decimal)
295/370	75/370	370/740	p (as fraction)
295.	75.	370.	X
370	370	740	n
	0.5946	difference
	0.	hypothesized difference
	0.0368	std. error
	0.5367	confidence interval 95.% lower
	0.6525	confidence interval 95.% upper
	0.0579	margin of error