To test the quality of its books, a printing press randomly picks a book from its press and then selects every twentieth book off the press for a half hour. Which sampling method is used?
lottery method
random number table
stratified random sampling
systematic random sampling

Abby is collecting rainfall data. she finds that one value of the data set is a high-value outlier. which statement must be true? abby will use a different formula for calculating the standard deviation. the outlier will increase the standard deviation of the data set. the spread of the graph of the data will not change. abby will not use the mean when calculating the standard deviation.