Answer:
99% Confidence interval: (17.9064,19.8136)
Step-by-step explanation:
We are given the following data set:
22,18,19,21,18,19,18,17,20,20,18,17,20,19,20,18,17,18,16,21,18,21
Formula:
where
are data points,
is the mean and n is the number of observations.
![Mean = \displaystyle\frac{\text{Sum of all observations}}{\text{Total number of observation}}](https://tex.z-dn.net/?f=Mean%20%3D%20%5Cdisplaystyle%5Cfrac%7B%5Ctext%7BSum%20of%20all%20observations%7D%7D%7B%5Ctext%7BTotal%20number%20of%20observation%7D%7D)
![Mean =\displaystyle\frac{415}{22} = 18.86](https://tex.z-dn.net/?f=Mean%20%3D%5Cdisplaystyle%5Cfrac%7B415%7D%7B22%7D%20%3D%2018.86)
Sum of squares of differences = 52.59
![S.D = \sqrt{\frac{52.59}{21}} = 1.58](https://tex.z-dn.net/?f=S.D%20%3D%20%5Csqrt%7B%5Cfrac%7B52.59%7D%7B21%7D%7D%20%3D%201.58)
99% Confidence interval:
Putting the values, we get,
Option A) With 99% confidence, the mean miles per gallon in the population of 2008 SUVs is somewhere in the interval.