A study of seat belt use involved children who were hospitalized after motor vehicle crashes. For a

group of 123 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 290 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 (based on data from some recorded research findings)

a.

Us 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. [Hint: STAT -TESTS -

2-SampleT Test, and then complete the required statistics] Select the appropriate one below and complete the required values.

2 - SampT Test

Inpt: [Data] OR Inpt: [Stats]

List1: L1

1:

x

List2: L2

1:

Sx

Freq1: 1

1:

n

Freq2: 2

2:

x

1: 2 2 2

2:

Sx

:

Pooled No Yes

2:

n

Calculate

1: 2 2 2

:

Pooled No Yes

Calculate.

What is the test statistics? ______________________

What is the P - Value? __________________________

Should we reject or accept H0? __________________________

Give reasons for your answer____________________________

State your conclusion in the context of the problem.

b.

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

[Hint: STAT -

TESTS -

2-SampTInt, and then complete the required statistics]

Select the appropriate one below and fill out the required values.

2 - SampTInt

Inpt: [Data] OR Inpt: [Stats]

List1: L1

1:

x

List2: L2

1:

Sx

Freq1: 1

1:

n

Freq2: 2

2:

x

:____________

C Level

2:

Sx

:

Pooled No Yes

2:

n

Calculate

:_______________

C Level

:

Pooled No Yes

Calculate.

What is the confidence interval?

Interpret your confidence interval in the context of the problem.