Interpreting Relationships

Mean and median are measures of center for a data set, while range and standard deviation are measures of spread.

The distribution of a variable provides all the possible values of the variable and how often they occur. 

You won’t be asked to calculate the standard deviation of a set of data on the SAT Math Test, but you will be expected to demonstrate an understanding of what standard deviation measures.

When asked to compare the standard deviations of two data sets, first locate the mean approximately. Then, ask yourself which data set has values that are more closely clustered around the mean. That data set will have a smaller standard deviation.

You won’t need to calculate margins of error on the SAT Math Test, but you should understand what the concept means and be able to interpret them in context.

When a margin of error is provided, determine the value to which the margin of error applies. If the margin of error is associated with a mean, then the margin of error describes the plausible values for individual values in the population.

In order for the results of a study to be generalized to an entire population, random sampling is needed. In order for a cause-and-effect relationship to be established, random assignment of individuals to treatments is needed.

Be wary of conclusions that claim a cause-and-effect relationship or that generalize a conclusion to a broader population. Before accepting a conclusion, assess whether or not the subjects were selected at random from the broader population and whether or not subjects were randomly assigned to treatments.