In: Statistics and Probability
During the current COVID-19 crisis, there have been several news polls regarding how well the President is handling the situation. A news poll happens when a news agency solicits responses through their news programs on televisions (or through the internet). A recent poll had the following results: Positive 43%, Negative 53%. However, broken down by political party, the results were as follows:
Political Party |
Positive |
Negative |
Republican |
85% |
15% |
Democrat |
13% |
85% |
First note that the numbers do not add up to 100%.
Explain why this type of poll is not statistically sound. You should give at least three reasons. Explain possible reasons why the results do not add to 100%. If you average the results across the parties, you do not get numbers that match the overall results. Considering the positive results, (85% + 13%) / 2 = 49%, not 43%. Similarly, the average of 15% and 85% is 50%, not 53%. Give a sound mathematical explanation of how that could happen?
The given probability are conditional & marginal probability. You have to convert it in joint probability