reference sheet 3 - week 1 to 4.pdf - Population All...

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Mean = Average, Median = Middle value, Mode = Most frequently occurring number. Range = Maximum value - minimum value IQR (Interquartile range) - IQR = Q3 - Q1. Standard Deviation - Square root of variance. = STEP ONE: Find the average = STEP TWO: Subtract the mean from each number and square the new average. Variance = Average of squared distance. Example: 2870, 2620, 3120, 3620. Population - “All American Millennials” Sample - “811 millennials that were surveyed” Parameter - “The percentage of all American Millennials who increased there physical activity with Pokemon go” Statistic - “% of the 811 American millennials surveyed who their physical activity with Pokemon go (84%)” Simple Random Sample (SRS) - When each possible sample of size n has an equal probability of being selected. Stratified Random Sample - Population is divided into strata/groups, SRS is obtained from each strata. Cluster Sample - Population is divided into clusters, take a SRS of entire clusters. Voluntary Response Sample - Individuals self-select to be part of the study/sample, biased, phone surveys. Convenience Sample - Selecting individuals based on how easy it is to access them. Selection bias - Sample is not representative of the population. Non-response bias - W hen the sample differs significantly from those not in the sample. Response Variable = Weight Loss, Explanatory Variable = Time spent playing Pokemon Go. Observational study vs. A well-designed experiment. Lurking variables - Unknown variable Correlation does not imply causation! WEEK ONE Mean Absolute Deviation (MAD) - Average distance (above or below) from the mean. Z-Score - Measure of how far a observation is from the standard deviation. Standard Z-Score = X - U X = Observation, U = Sample Mean = x ̅ O O = Sample Standard deviation. To identify exceptionally large observation |Z| > 3. WEEK THREE Probability of an event = P(event) = # of points in the event Example: In rolling a 6-sided die, what is the probability Total # of points in the sample space of A. What is the probability that we roll an even Rules of probability - All probabilities lie between 0 & 1, number? A = {2,4,6} -> P(A) = 3/6 = 0.5 and for any sample, total probability has to be 1. Intersection of events - A n B = Intersection…
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