# Thread: need a help urgent >>>

1. ## need a help urgent >>>

hi everyone;

befor 2 days was my first lecture in stats so i couldnot understand parameter and sample so please help me in answering this example:

According to the financial time newspaper (15-10-1987), the average size of an UK household had fallen from 3.14 persons in 1970 to 2.66 persons in 1987.

a) The 1987 figure of 2.66 is claimed to be the value of a population parameter. What are the population and the parameter?

b) What procedure must be taken to be 100% certain that the value of the population parameter is exactly 2.66?

c) What procedure was likely used to arrive at the 1987 figure of 2.66? Use the terms sample, sample statistic, and inference in your answer.
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2. If I understand your question correctly, then:

a) a population is a set which interest you. the population in your case is all the houses in the UK. you are interested in the size of them. the parameter is an attribute of the population, usually it's something you do not know and want to find out. in this case, the parameter is the "average size of a UK household", which I would have defined "expectation" rather than "average", but you won't understand why at that stage. another definition of population can be the distribution of the data, but it's a more abstract definition.

b) in order to be 100% sure, and I repeat, 100% sure, you must check every house in your population, not other way.

c) since checking the entire population is not reasonable, some other procedure was probably taken. a sample, which is a subset of the population was taken, let's say, for example 300 houses. then an average of this sample was calculated, and was used for inference on the parameter we want to find out. inference means taking the sample, calculating some value from it ( called "Statistic", in this case the average, and using the statistic to predict the true value of the parameter we want, in this case the population's average.