MATH1280 Statistics 1 Discussion forum UNIT1
Grades 9.80/0-10
INSTRUCTION
Random variables are used to model situations in which the outcome, before the fact, is uncertain. One component in the model is the sample space. The sample space is the list of all possible outcomes (or a range of possible values). For each value in the sample space, there is an associated probability. The probability can either be an estimate of something that exists in the real world or it could be an exact value that comes from an ideal distribution. Sometimes identifying the sample space helps to remind you exactly what it is that you are measuring.
Think of something that you might want to measure that is affected by random variation. Identify what you want to measure, then describe its (approximate) sample space. Give a rough description of the probabilities associated with those values (you can simply specify if they are all the same probability or if values in one range will be more likely than values in another range). What would you say to a person who says that he or she "knows" what the outcome of an individual observation will be (an outcome of something that has not happened yet that is subject to random error)?
When forming your answer to this question you may give an example of a situation from your own field of interest for which a random variable can serve as a model.
There is no requirement to use sources from the Internet, but if you use an idea or a quotation from any source, it should be cited (such as putting the author and year at the end of the sentence and then adding a reference at the end to describe the source).
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1. Think of something that you might want to measure that is affected by random variation. Identify what you want to measure, then describe its (approximate) sample space. Give a rough description of the probabilities associated with those values (you can simply specify if they are all the same probability or if values in one range will be more likely than values in another range).
I will measure how likely it is for persons who develop lung cancer after a decade. A population of 100,000 persons and the approximate sample space is comprised of 4 potential outcomes. The probability that persons who smoke constantly develop lung cancer will be the same throughout the data. Factors such as the subjects' age, gender, and habits also affect the outcome result.
2. What would you say to a person who says that he or she "knows" what the outcome of an individual observation will be (an outcome of something that has not happened yet that is subject to random error)? When forming your answer to this question you may give an example of a situation from your own field of interest for which a random variable can serve as a model.
Variability is associated with uncertainty, so we can never know what the outcome of an individual observation will be. We can guess, but we can not know the outcome. We can know the outcome of an individual observation in case of the idea of randomness is associated. For example, in Japan, the number of households that do not have landlines at home and use only mobile phones has been increasing recently. When I collect data about houses that have and do not have landlines, there is a high degree of variability, especially in urban areas of Japan. I can not know for sure which household has landlines.
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