Discussion 1: Confidence Intervals

To prepare for this Discussion, consider the following scenario:

Polls will often present candidates running for election as winning or losing based on the results of recent surveys. When presenting the poll, there is usually information about a “margin of error.” What does that mean?

For example, consider that one survey, conducted by a professional polling organization, shows Candidate Q with 49% with a plus or minus margin of error of 2 percentage points (usually depicted as ±2%). The same survey shows the other candidate, Candidate Z having an estimated 47% of likely voters and the same margin for error (±2%).

However, consider that another survey taken of the same population in the same day by a different professional polling organization has different results. In this survey, Candidate Z has polled at 49% while Candidate Q, has only polled at 46%. This survey has a 3-percentage-point margin of error (±3%).

Post a 200- to 250-word explanation, listing the assumptions you would have to make to be able to use the information given in the polls and draw conclusions about a potential outcome. Finally, based on what you know about confidence intervals, take your best guess about which candidate you believe is really ahead in the race. Justify your rationale and explain clearly how the assumptions you made affect your prediction.

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