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Published byLily Sparks Modified over 9 years ago
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H1H1 H1H1 HoHo Z = 0 Two Tailed test
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Z score where 2.5% of the distribution lies in the tail: Z = + 1.96 Critical value for a two tailed test.
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85 5% One tailed test
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85 5% One tailed test
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Z score where 5% of the distribution lies in the tail: Z = + 1.65 Critical value for a one tailed test.
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Z scores require and What happens when the population mean is known but the standard deviation is unknown?
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T test for single samples
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is the standard error of the mean, estimated.
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S is representing the standard deviation of the sample, as an estimate of the population.
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n - 1 represents degrees of freedom. (df) Degrees of freedom: the number of values that are free to vary.
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Computational Formula Standard deviation of a sample as an estimate of the population.
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Situation that calls for a t test for single samples: 1) Population mean is know n. 2) The standard deviation of the population is unknown. 3) A sample of a specific size is available.
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Steps for a single sample t test: 1) compute the standard deviation as an estimate of the population. 2) compute the standard error estimated 3) compute t 4) evaluate the computed t value to determine if it is statistically significant.
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The t distribution: - Symmetric - Flatter middle than a normal distribution. Fatter tails.
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Critical value = 2.262
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