Probability and Statistics, WGU C955

Boxplot - answer-an image that has min, Q1, median, Q3, max Histogram - answer-A graphical representation -- bars, measuring the frequency within each interval Skewed right - answer-Not a symmetric distribution, the tail is on the right, i.e. extra stuff on the right Measures of center - answer-Median, the mean (and mode) Measures of spread - answer-Range, IQR & standard deviation Standard Deviation Rule - answer-68% of the data are within 1 standard deviation, 95% are within 2, 99.7 are within 3 standard deviations from the mean. For skewed data, use these for center and spread - answer-In this situation, we use median (for center) & IQR (for spread) Explanatory variable - answer-In a study, what we think is the "cause" Response variable - answer-In a study, what we think is the "effect" Scatter plot - answer-A graphical representation of Q -> Q Two way table - answer-A graphical representation of C -> C Side-by side box - answer-A graphical representation of C -> Q Linear relationship - answer-"shaped like a line" Correlation coefficient, r - answer-Between -1 and 1; measures how close the points are to the line and if the trend is uphill (positive) or downhill (negative). r = -0.2, for example - answer-This is an example of a correlation coefficient that represents a weak negative correlation. r = 0.9, for example - answer-This is an example of a correlation coefficient that represents a strong positive correlation. Linear regression line - answer-A line that fits the data as close as possible, used to make predictions Interpolation - answer-Making predictions *within* the range of your data. This is usually accurate. Extrapolation - answer-Making predictions *outside* of the range of your data. This is generally a bad idea. Simpson's Paradox - answer-When split up, each data set can have a pattern which goes away when all the data is combined. Only way to prove causation - answer-Experiments, because they account for lurking variables Observ