Litter

[groovy chick]

If some people think that the percentage of people drop litter everday is much lower than 93 percent , and then 10 people were asked if they drop litter everyday, what reasons are there that might not give very good data on this.

[CheekyChops]

I don't even think I understand the question...

The 10 people might lie - if someone asked me if I dropped litter on a daily basis, I would say no, whether I did or not!

[WaldoMcFroog]

It's to do with whether the sample is sufficiently high for the population under study to be able to say with any confidence that their answers reflect that of the larger population.

You don't say whether the population under study is 'the whole of the UK' or 'the world' or 'Harrogate' or whatever, but it matters little.

The standard used by Market Research People is 95% /- 5%. This means that you can be 95% confident that the responses to a given question are within +/- 5% of what the entire population would say if asked.

If we say you were talking about Harrogate, which has a population of circa 90,000, then you need to interview just 383 people to achieve 95% /- 5%. In fact, for just 9,000 population, you still only need interview 368 people. For 900, 269 and for 90, it's 73.

The following link gives more details.

http://www.surveysystem.com/sscalc.htm