Most people use fractions in their everyday life when they talk about time (quarter after ten), parts of pizzas and cakes (halves and quarters) or when shopping (two-thirds off marked prices). You may also see fractions in the headlines. The following headline appeared in a press release from the British Wind Energy Association in June 2005.
“Three-quarters of people in Wales believe wind farms are necessary, says new poll.”
What did you think when you read the headline? Do a majority of the Welsh support this view? Do you know how many people actually think in this way?
No, you don’t actually know the number of people who think this way; the headline just tells you the proportion of those who support wind farms out of the group of people who were interviewed. If you gathered together all the people who were polled, you could arrange them into four equal groups, so that the people in three of the groups would have supported this view, and those in the fourth would not.
If only four people had been interviewed, three would have agreed that wind farms are necessary. If 4,000 people were interviewed, then 3,000 would have agreed, and so on. So, how much notice you should take of the headline would probably depend on both the number of people who were surveyed and how they were selected.
Interviewing a lot of people who had been selected at random may give a better indication of the views of the general population than polling just a few people who lived a long way from any wind farm would.
BWEA (2005) BWEA Press Release (accessed August 26, 2011).