science and stats

# science and stats - Descriptive statistics gives us...

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is there one right kind of science? (1) devising alternative hypotheses (2) devising a crucial experiment . .. with alternative outcomes . .. each of which will . .. exclude one or more of the hypotheses It is like climbing a tree. [focus] on the exclusion of a hypothesis How small and elegant an experiment can you perform? You must study the simplest system you think has properties you are interested in. ...there is no such thing as proof in science. .. science advances only by disproofs. Doing an experiment In an experiment: An independent variable is what I’ll manipulate A dependent variable is what I’ll measure The population is everything out there The sample is what, out of the population, I’ll measure (to make inferences about the population) Sampling - random sampling is best
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Unformatted text preview: Descriptive statistics gives us averages (means) as well as measurements of how variable the data are (standard deviations) In inferential statistics we propose a null hypothesis vs. an alternative hypothesis. Doing statistics Hypotheses are small questions. The normal distribution Area under the curve = 1 Middle of the curve is the mean, 0 in the &quot;standard&quot; normal distribution variation is indicated by standard deviation z-score indicates the number of standard deviations away from the mean the a score is About 5% of the curve is 2 or more standard deviations from the mean Central limit theorem: The distribution of sample averages approaches the normal distribution as the sample size increases (It's a theorem, that means it can be proven, it's not just an idea)...
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## This note was uploaded on 04/14/2011 for the course BIO 120 taught by Professor Stark during the Fall '08 term at Saint Louis.

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