On a 100 point scale on overall approval for a list of well known Canadians a random sample of 1,800 Canadians report a mean approval rate of 55 with standard deviation 20. On the basis of this information 

 

Calculate the Standard Deviation

2. The distribution of a sample of 1,500 Americans in which post-911 960 state they believe the US is winning the war on terror and the remainder say it is not.
4. The distribution of 900 Canadians of whom 225 say they have attended university and the remainder say that they have not.