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New Zealand
Level 7 - NCEA Level 2

Real Life Data - Opinion Polls (Investigation)


Data on the News


You may have come across “opinion polls” if you follow the news. Opinion polls, or simply polls, attempt to measure what people – the entire population – think about a subject or person. They do this by asking just a few thousand people (a sample). From the responses provided by this small group, we can then try to represent the opinions of the entire population. The figure to the right is an example of a poll in the US that was taken concerning the performance of president Barack Obama. Whilst this polling may not be entirely accurate, the samples are always chosen with the aim of being representative of the population.


  1. Did the majority of people think the country was going in the right direction?
  2. What percentage of people had a belief about what direction the country was heading in?
  3. What percentage of people strongly approved of Obama?
  4. What fraction of people disapproved of Obama?
  5. Was strong approval of Obama more common or less common than strong disapproval?
  6. Do you think there is a link between whether voters think the country is going in the right direction and what voters think of Obama? Can you think of a reason for this?
  7. If this poll had actually been taken on 200 people, how many of these people would have said they approved of Obama?
  8. What about if the poll had been taken on 500 people?
  9. Draw a histogram of the data on Obama’s approval rating.


Go to the Newspoll website and click on “Opinion Polls” >> “Latest Polls” >> “Federal voting intention and leaders’ rating” (for the most recent period). Answer the following questions by referring to the most recent poll in the report.

  1. According to this poll, which party would receive the majority of the primary vote?
  2. Which party is ahead on a two party preferred basis?
  3. Is the satisfaction rate with the performance of the prime minister higher or lower than the dissatisfaction rate?
  4. Are people more satisfied or less satisfied with the performance of the prime minister than the performance of the opposition leader?
  5. Which candidate did most people think would make the better prime minister?
  6. Do you think there is a link between people’s level of satisfaction with the two leaders’ performances and which leader they think would make the better prime minister? Discuss.
  7. Do you think there is a link between who people think would make the better prime minister and the party they would vote for? Discuss



S7-3 Evaluate statistically based reports: A interpreting risk and relative risk B identifying sampling and possible non-sampling errors in surveys, including polls


Evaluate a statistically based report

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