Listed below are the April utility bills (in dollars) for one neighborhood. Assuming that the data is normally distributed, test the claim that the standard deviation for the data is $15. Use α =...

Listed below are the April utility bills (in dollars) for one neighborhood. Assuming that the data is normally distributed, test the claim that the standard deviation for the data is $15. Use α = 0.01.

78, 61, 42, 80, 89, 55, 75, 90, 66, 82, 49

Apply  classical approache.  Show step1-step3.

Round test statistic to nearest thousandth.

Could you also include the margin, I'm a bit confused on the margin. And please show me the steps.