Answer:
99% Confidence interval: (63.65,69.65
Step-by-step explanation:
We are given the following data:
63, 68, 60, 59, 68, 65, 67, 64, 69, 69, 61, 67, 61, 60, 66, 67, 68, 66, 70, 79, 76, 75, 65
Formula:
[tex]\text{Standard Deviation} = \sqrt{\displaystyle\frac{\sum (x_i -\bar{x})^2}{n-1}}[/tex]
where [tex]x_i[/tex] are data points, [tex]\bar{x}[/tex] is the mean and n is the number of observations.
[tex]Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}[/tex]
[tex]Mean =\displaystyle\frac{1533}{23} = 66.65[/tex]
Sum of squares of differences = 575.217
[tex]S.D = \sqrt{\dfrac{575.217}{22}} = 5.11[/tex]
99% Confidence interval:
[tex]\bar{x} \pm t_{critical}\displaystyle\frac{s}{\sqrt{n}}[/tex]
Putting the values, we get,
[tex]t_{critical}\text{ at degree of freedom 22 and}~\alpha_{0.01} = \pm 2.818[/tex]
[tex]66.65 \pm 2.818(\dfrac{5.11}{\sqrt{23}} ) = 66.65 \pm 3.002 = (63.65,69.65)[/tex]
