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 Part 1. Explain the concept of ‘margin of error’ in deciding the size of a sample 

 Part 2 – Explain the following terms with an example 


  • Point estimate
  • Interval estimate
  • Confidence interval
  • Confidence limits
  • Confidence coefficients or critical values.

Part  3 – In a survey carried out in a large city, 170 households out of a  random sample of 250 owned at least one pet. Find the 95 per cent  confidence interval for the percentage of households in the city who own  at least one pet. Does the result support a pet food manufacturer’s  claim that 75 per cent of all households have at least one pet?