# Population Means

Infants weighing more that 1700 grams who require respiratory assistance within the first 24 hours of birth and met other clinical criteria. The following table is a result of measurements of plasma volume (ml) made during mechanical ventilation.

subject / sample sz/ sample mean/ sample st. dev.

paralyzed/ 5 48.0 8.1

nonparalyzed/ 7 56.7 8.1

You may assume equal standard deviations. Construct a 98% confidence interval for the difference of the two population means.

Do you think there is a difference between the two population means?

#### Solution Preview

Construct the 98% confidence interval for the difference of the two population means

<br>Let Md=µ1- µ2= 56.7 - 48.0 = 8.7

<br>The estimated standard error, SMd, is computed assuming that the variances in the two populations are equal. when n1 ≠ n2. The formula for MSE is:

<br>MSE = SSE/df

<br>where df is the ...

#### Solution Summary

Infants weighing more that 1700 grams who require respiratory assistance within the first 24 hours of birth and met other clinical criteria. The following table is a result of measurements of plasma volume (ml) made during mechanical ventilation.

subject / sample sz/ sample mean/ sample st. dev.

paralyzed/ 5 48.0 8.1

nonparalyzed/ 7 56.7 8.1

You may assume equal standard deviations. Construct a 98% confidence interval for the difference of the two population means.

Do you think there is a difference between the two population means?