WGU C955 Latest Update Already Graded A

WGU C955 Latest Update Already Graded A Histogram A graphical representation -- bars, measuring the frequency within each interval Skewed right Not a symmetric distribution, the tail is on the right Measures of center Median, the mean (and mode) Measures of spread Range, IQR & standard deviation Standard Deviation Rule 68% of the data are within 1 standard deviation, 95% are within 2, 99.7% are within 3 standard deviations from the mean. median (for center) & IQR (for spread) skewed data uses these for center and spread Scatter plot A graphical representation of Q -> Q Two way table A graphical representation of C -> C Side-by side box A graphical representation of C -> Q Interpolation Making predictions *within* the range of your data. This is usually accurate. Extrapolation Making predictions *outside* of the range of your data. This is generally a bad idea. Simpson's Paradox When split up, each data set can have a pattern which goes away when all the data is combined. Prospective study Is a study that's done over time to find results / A study watching for outcomes during the study period Unbalanced response Giving more options that are negative than positive options (or vice versa) which biases the responses towards the more common option Matched pairs Grouping two similar subjects and giving different treatments/procedures to each in order to compare the differences. For example, having one twin take a medication while the other twin does not. Population The entire group you are trying to describe or understand. Sampling frame List of group from which you choose your sample. Sample The group that is actually picked to be included in a study Simple random sample making a selection by following a random pattern and selecting without replacement. Unbiased. Systematic sample Sample is selected by listing the sampling frame, then making a selection by following a simple pattern (eg. Every 20th name). Unbiased. Voluntary sample Members of the sample may choose not to respond. Similar to Non Response. Convenience sample Participants are easy for researcher to access. Tends to increase bias. Cluster sample Sample frame is divided into groups, we select a few groups, then selecting ALL of the members of those groups. Stratified sample Sample frame is divided into groups. Then we choose a random sample (usually the same size) from within EVERY group. Multi-stage sample Multiple rounds of randomness and grouping. For example: randomly selecting a few groups, then choosing a small random sample just those selected groups. Often a combination of Cluster and Stratified Sampling. P(A)*P(B) independent events: P(A and B) = P(A|B) P(A and B) ÷ P(B) P(A or B) P(A) + P(B) - P(A and B) P(A and B) P(A)*P(B|A) Box plot an image that has 5 number summary: min, Q1, median, Q3, max, nCr = n! / r!(n - r)! probability combination formula