In a recent survey, 10 percent of the participants rated Pepsi as being "concerned with my health." PepsiCo's response included a new "Smart Spot" symbol on its products that meet certain nutrition criteria, to help consumers who seek more healthful eating options. Suppose a follow-up survey shows that 13of 100 persons now rate Pepsi as being "concerned with my health." Calculate the z statistic. (Round your answer to 3 decimal places.) z_calc _____________