ABER-RANT

If you wish to find out something about a particular population , and it is not feasible to test the whole population, then you may test a sample of that population providing that the sample is an accurate refection of the population. In order to get a valid sample one needs to select randomly across the the entire population. Something to be avoided is self-selection.; this is in fact the major flaw in virtually all drug trials, in that they ask for volunteers, and this leads to bias. You might be thinking What's wrong with using volunteers? Well, consider the following: Suppose you wished to ascertain the feeling of the general public towards the recent Olympic games. You might perhaps create a web-site asking people to complete a survey about the games. The flaw in the sample is here quite easy to spot. Only those who were interested in the games would volunteer, and therefore your sample would not reflect the the general population, some of whom must not be interested in...

It is a complete myth that smokers die prematurely smoking rarely kills male ever-smokers before 50 years of age and female ever-smokers before 55 years of age, and does so very rarely at earlier ages. While deaths attributed to smoking do occur much more frequently with increasing age, so too do deaths from other causes and it is not clear how the ever-smoker's age-increasing annual risk of death due to his or her smoking should be apportioned between smoking on the one hand and simply aging on the other. The anti-smoking movement's message that smoking kills has to be interpreted from the balanced perspective of not only how likely it is to do so; but of how likely it is that other causes will pre-empt that possibility by leading to death before it eventuates. For instance, while it may be a cause of concern to a 65 to 69 year old male ever-smoker, and to a 70 to 74 year old female ever-smoker to be told that they have a yearly chance of about 1 in 100 that their smoking wil...