Question

Q. 11

A study of seat belt use involved with children who were hospitalized after motor vehicle crashes. For a group of 121 children who were wearing seat belts, the number of days in intensive care units (ICU) has a mean of 0.83 and a standard deviation of 1.77. For a group of 156 children who were not wearing seat belts, the number of days spent in ICUs has a mean of 1.39 and a standard deviation of 3.06.

a.     Use a 0.05 significance level to test the claim that children wearing seat belts have a lower mean length of time in an ICU than the mean for children not wearing seat belts.

b.     Construct a confidence interval appropriate for the hypothesis test in part a)

c.     What important conclusion do the results suggest?

Answer 1

Given,

Children wearing seat belt,

Children not wearing seat belt,

a.

The hypothesis is,

We know that,

Corresponding p value is 0.0280

Since the p value is less than the level of significance, we reject the null hypothesis.

b.

The confidence interval is,

C. I. = [-1.0421, - 0.0779]

The conclusion that the result suggests is, that the children wearing seat belt spends less time in ICE than.