Question

A community health association is interested in estimating the average number of maternity days women stay in the local hospital. A random sample is taken of 36 women who had babies in the hospital during the past year. The following numbers of maternity days each woman was in the hospital are rounded to the nearest day.

5	3	4	3	2	5	3	1	4	3
4	2	3	5	3	2	4	3	2	2
1	6	3	4	3	3	5	2	3	4
3	5	4	3	5	5

Use these data and a population standard deviation of 1.14 to construct a 98% confidence interval to estimate the average maternity stay in the hospital for all women who have babies in this hospital.

(Round the intermediate values to 3 decimal places. Round your answers to 3 decimal places.)

Answer 1

We have for given data,              
              
Sample mean =3.39      
Population standard deviation=1.14  
Sample size=36      
Level of significance =   1-0.98=0.02      
Z critical value (by using Z table)=2.326      
              
Confidence interval formula is              


=(2.948,3.832)
          
Lower confidence limit =2.948  
Upper confidence limit =3.832