A random sample of the houses in a particular city is select…

A random sample of the houses in a particular city is selected and the level of random gas is measured for each house in the sample.  The values collected are given below in parts per million (ppm).  Experience has shown that random gas level is approximately normally distributed for this population.  4, 8, 13, 6, 7, 3, 9, 8, 11, 8 Find a 95% confidence interval for