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Table of Contents Math Background Introduction to Probability Events and Sample Space | |
See also: random sampling |
When we perform the experiment of throwing a die and recording the number
on the top face, we have six possible outcomes of this experiment. For
each experiment we can observe one and only one of these six basic outcomes
and the outcome cannot be predicted with certainty. The outcome cannot
be broken down into more basic outcomes. The collection (set) of all basic
outcomes is called sample space. Since observing the outcome of
an experiment is similar to selecting a sample from a population (in our
case the sample space), the basic outcomes are called sample points.
Experiment | An experiment is an act of observation that leads to a single outcome that cannot be predicted with certainty. |
Sample Point | A sample point is the most basic outcome of an experiment. |
Sample Space | The sample space of an experiment is the collection of all its sample points. |
Event | An event is a specific collection of sample points. |
What are the sample points of the experiment of tossing two coins and recording their up face?
It is important to note that we have to distinguish between the cases where coin 1 shows head and coin 2 tail and when coin 1 shows tail and coin 2 head, despite the fact that the coins appear to be identical. So we have four different possible outcomes (sample points) and our sample space is:HH HT TH TT H ... head, T ... tailA compounded event would be: throwing exactly one head, since it would consist of two sample points: HT and TH.
Last Update: 2006-Jän-17