Question

A random sample of 30 households was selected from a particular neighborhood. the number of cars for each household is shown below. estimate the mean number of cars per household for the population of households in this neighborhood. give the 95% confidence interval.

a. 1.14 to 1.88
b. 1.12 to 1.88
c. 1.12 to 1.98
d. 1.14 to 1.98

Answer 1

The number of cars for each household is:

2 0 1 2 3 2 1 0 1 4
1 3 2 0 1 1 2 3 1 2
1 0 2 2 1 2 2 1 0 2

Getting the average of this will give us: 45/30 = 1.5

So n is 30

Standard deviation is: 1.00858

95% confidence level is equal to 1.960 z value

So, confidence interval is calculated by: mean ± z s/ √n

So plugging in our data:

= 1.5 ± (1.960) 1.00858/ √30

= 1.5 ± (1.960) 0.184140672

= 1.5 ± 0.360915717

= 1.14 < x < 1.8

Therefore, the answer is A.