Describe the sample paint a picture sense the data

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[Describe the sample; paint a picture; sense the data] Location – Central tendency of the data (mean, median, mode) o Mean – Average o Median – Central Point Eg. 3 5 2 4 (no one median) 2 3 4 5 (choose 2 in the middle) o Mode – Most frequent occurring Spread – Variability in the data (range, standard deviation) o Range – maximum-minimum (difference between max and min) o Standard Deviation – average deviation; average distance of the distribution values from the mean Shape – Pattern indicated by the data (histogram) o Left skewed (highest point on the right) o Symmetric (highest point in the middle) o Right Skewed (highest point on the left) o Bi-model shape (two highest points) not good for data to have this (either data collected incorrectly or used wrong scale) Consistency – Performance over time Downloaded by:: bryce0736 | [email protected] Distribution of this document is illegal
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Stuvia.com - The study-notes marketplace Inferential Statistics: to infer form the same data what the population might think. We use inferential statistics to make judgments of the probability that an observed difference between groups in a dependable one or one that might have happened by chance in the study. Hypothesis testing o Means o Variances o Proportions Regression Examples: Enables use of one or more samples of observation to infer values of a population Test hypothesis to determine if observed differenced between groups of variables are real or occur simply by chance Produces new information by making predictions and generalizations based on samples Uses data to estimates or influences about population based upon sample Parameter estimating – estimating a parameter based on a sample Confidence interval Sample size Sample Standard deviation Sample mean Downloaded by:: bryce0736 | [email protected] Distribution of this document is illegal
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Stuvia.com - The study-notes marketplace X- bar: 54 X- bar: 50 Confidence level Statistical Significance: Definition: The significance level, also denoted as alpha or α, is the probability of rejecting the null hypothesis when it is true. For example, a significance level of 0.05 indicates a 5% risk of concluding that a difference exists when there is no actual difference. Why do we look at statistics? To summarize the information and to form a picture to interpret the information easily Why do we look at inferential statistics? To look at how the probability is linked to a certainty or confidence Confidence Interval = 48 - 52 Sample 1 X=54 X=50 Downloaded by:: bryce0736 | [email protected] Distribution of this document is illegal
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Stuvia.com - The study-notes marketplace TEST Ho Ha TEST Ho Happy α Ha β Happy If p < a→Ha If p≥a→ Ho Y = Output Variable (contribute) X = Input Variable (attribute) Mean o Anova (3+) o T-tests (2 of 1) Variance (Standard Deviation) Proportionate The test of Significance: Test of statistical significance can be used to determine the extent to which chance has operated
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