WGU C955.docx

median vs IQR - correct answer skewed data uses these for center and spread Histogram - when to use - correct answer Based on the shape of the distribution, uses mean + standard deviation OR median + IQR to describe center and spread - Larger data sets; shows shapes of distribution and potential outliers; ignores the individual data valuesl Histogram Skewed right - correct answer Not a symmetric distribution, the tail is on the right Standard Deviation Rule - correct answer 68% of the data are within 1 standard deviation, 95% are within 2, 99.7% are within 3 standard deviations from the mean. Scatter plot - correct answer A graphical representation of Q - Q If relationship is linear (confirmed using the scatterplot), use the correlation coefficient to describe strength of relationship and the least-squares regression line to make predictions Two way table - correct answer A graphical representation of C - C Relative frequencies OR conditional percentages for each row/column of the explanatory variable Side-by side box - correct answer A graphical representation of C - Q 5-number summaries of the response variables Interpolation - correct answer Making predictions *within* the range of your data. This is usually accurate. Extrapolation - correct answer Making predictions *outside* of the range of your data. This is generally a bad idea. predictions for data larger than the maximum x-value or smaller than the minimum x-value of the known data points Simpson's Paradox - correct answer When split up, each data set can have a pattern which goes away when all the data is combined. can only occur when the sizes of the groups are inconsistent Population - correct answer The group you want to study Sampling frame - correct answer the list of people or things you pull the sample from Sample - correct answer the subset of the population that is actually being studied Simple random sample - correct answer participants are randomly chosen from the entire population Voluntary sample - correct answer researchers invite everyone in the sampling frame to participate,those who respond make up the sample. Cluster sample - correct answer some groups are chosen, all people within those groups are studied Stratified sample - correct answer all groups are chosen, only some people within each group arestudied P(A)*P(B) - correct answer independent events: P(A and B) = P(A|B) or P(BIA) - correct answer P(A and B) ÷ P(B) or P(A and B) ÷ P(A)