Statistic Question

Using the data in BELOW find the 99% confidence interval for the variance AND standard deviation of the ages of the babies born at this particular hospital this year. 

____________________________________________________________________

The data shown below represents the ages in months of 25 babies born at a particular hospital this year. Babies who are less than a month old are given an age of 0 months.

092310011131284714766156784

 Find the 95% confidence interval for the mean age of the babies born at this particular hospital this year.

The mean (average) X is given calculated as 

X = Sum of all the ages of babies / Number of babies

X = 116/25

X = 4.64 months

Standard Deviation = SD = 3.2259

The degree of freedom = d.f. = n – 1 = 24

 

The t value is tα/2 = t0.025 = 2.0639

The 95% confidence interval is given as

X +/- tα/2 S/n  

4.64 +/- ((2.0639*3.2259)/25)