You are watching TV with a friend of yours, who was not luckyenough to go to business school and take a course on marketingresearch. On TV, a journalist explains that, according to thelatest poll, “pollsters are confident at 95% that 64% (+ or – 3%)of the French voters would vote for Mr. Biden and 36% (+ or – 3%)for Mr. Trump, if the presidential elections were held today”. Thejournalist adds that those results are based on a poll conductedamong 1,054 registered voters.
Your friend tells you that “It’s ridiculous to interview only1,054 people and believe you can generalize your findings to apopulation of millions of people… You have to interview ALL theU.S. registered voters if you want your findings to be accurate! Acensus is always better that a poll based on a sample!” Based onwhat you have learned in this course,
(1) explain to your poor friend why she is not right.
Also, (2) tell her what pollsters mean by “margin of error” and“confidence interval”.
