A simple random sample offront-seat occupants involved in car crashes is obtained. Among

2847

occupants not wearing seatbelts,

30

were killed. Among

7833

occupants wearing seatbelts,

17

were killed. Use a

0.01

significance level to test the claim that seat belts are effective in reducing fatalities. Complete parts(a) through(c) below.

Test the claim using a hypothesis test.

Consider the first sample to be the sample of occupants not wearing seat belts and the second sample to be the sample of occupants wearing seat belts. What are the null and alternative hypotheses for the hypothesistest?

A.

H0:

p1p2

H1:

p1p2

B.

H0:

p1p2

H1:

p1=p2

C.

H0:

p1=p2

H1:

p1>p2

D.

H0:

p1p2

H1:

p1p2

E.

H0:

p1=p2

H1:

p1p2

F.

H0:

p1=p2

H1:

p1

Part 2

Identify the test statistic.

z=

(Round to two decimal places asneeded.)

Part 3

Identify theP-value.

P-value=

(Round to three decimal places asneeded.)

Part 4

What is the conclusion based on the hypothesistest?

TheP-value is less than? Or greater than?

the significance level of

=0.01,

so reject? Or unrejected?

the null hypothesis. There is? Or there is not?

sufficient evidence to support the claim that the fatality rate is higher for those not wearing seat belts.

Part 5

b. Test the claim by constructing an appropriate confidence interval.

The appropriate confidence interval is

(Round to three decimal places asneeded.)

Part 6

What is the conclusion based on the confidenceinterval?

Because the confidence interval limits do not include? Or include?0, it appears that the two fatality rates are equal? Or not equal?

Because the confidence interval limits include only positive? Only negative? Or both?

values, it appears that the fatality rate is higher? Lower? Or the same?

for those not wearing seat belts.

Part 7

c. What do the results suggest about the effectiveness of seatbelts?

A.

The results suggest that the use of seat belts is associated with the same fatality rates as not using seat belts.

B.

The results suggest that the use of seat belts is associated with lower fatality rates than not using seat belts.

C.

The results suggest that the use of seat belts is associated with higher fatality rates than not using seat belts.

D.

The results are inconclusive.