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BES Tutorial Sample Solutions, S1/11
WEEK 2 TUTORIAL EXERCISES (To be discussed
in the week starting March 7)
1.
What is meant by a variable in a statistical sense?
Distinguish between qualitative and quantitative
statistical variables, and between continuous and
discrete variables.
Give examples.
A variable in a statistical sense is just some
characteristic of an ‘object’. It may take different values.
Data on a quantitative variable can be expressed
numerically in a meaningful way (e.g. height of an
individual, number of children in a family.
Data on
qualitative variables cannot be expressed numerically in
a meaningful way; e.g. sex of an individual, hair colour).
A discrete quantitative variable can assume only certain
discrete numerical values on the number line (can be a
finite or infinite number of these values).
A continuous
quantitative variable can assume any value in a specific
range or interval; e.g. length of a pipe.
2.
Distinguish between (a) a statistical population and a
sample; (b) a parameter and a statistic. Give examples.
A statistical population is the set of measurements or
observations of a characteristic of interest for all
elementary units in a frame; e.g the shoe sizes of all men
in Australia.
A statistical sample is a subset of a
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population; e.g. the shoe sizes of all the men in the class
is a sample of the population represented by the shoe
sizes of all men in Australia.
A parameter is a numerical description of a population.
For example, the average shoe size of all Australian men
is a parameter (of the population of the shoe sizes of all
Australian men). A statistic is a numerical description of
a sample. For example, the average shoe size of all men
in this class room is a statistic (calculated from the
sample of the shoe sizes of all men in this class room).
3.
In order to know the market better, the secondhand
car dealership, Anzac Garage, wants to analyze the
age of secondhand cars being sold. A sample of 20
advertisements for passenger cars is selected from the
secondhand
car
advertising/listing
website
www.drive.com.au
The ages of the vehicles at time of
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 Three '11
 DenzilGFiebig

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