WGU C955 Test Questions With Verified Answers

median vs IQR - Answer skewed data uses these for center and spread Histogram - when to use - 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 - Answer Not a symmetric distribution, the tail is on the right 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. Scatter plot - 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 - Answer A graphical representation of C -> C Relative frequencies OR conditional percentages for each row/column of the explanatory variable Side-by side box - Answer A graphical representation of C -> Q 5-number summaries of the response variables 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. predictions for data larger than the maximum x-value or smaller than the minimum x-value of the known data points Simpson's Paradox - 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 - Answer The group you want to study Sampling frame - Answer the list of people or things you pull the sample from Sample - Answer the subset of the population that is actually being studied Simple random sample - Answer participants are randomly chosen from the entire population Voluntary sample - Answer researchers invite everyone in the sampling frame to participate,those who respond make up the sample. Cluster sample - Answer some groups are chosen, all people within those groups are studied Stratified sample - Answer all groups are chosen, only some people within each group arestudied