Must be solved using Excel

Question:

The newscasters usually report something such as, "44.9% of the population approve or strongly approve of the President's handling of the environment. The margin of error in this result is plus or minus 3%." Where does this 3% comes from? If the pollsters want the margin of error to be plus or minus 3%, how does this lead to a sample size of approx. 1000?

'40. Referring to the previousproblem, you often hear the results of such a poll in the news. In fact, the newscasters usually report something such as, \"44.9% of the population approve or strongly approve of the President's handling of the environ- ment. The margin of error in this result is plus or minus 3%.\" Where does this 3% comes from? If the pollsters want the margin of error to be plus or minus 3%, how does this lead to a sample size of approximately 1000? lI