Statistics and Probability offers students an alternative to Precalculus as a fourth high school mathematics course. 

In the Statistics and Probability course, students continue to develop a more formal and precise understanding of statistical inference, which requires a deeper understanding of probability. Students learn that formal inference procedures are designed for studies in which the sampling or assignment of treatments was random, and these procedures may be less applicable to non-randomized observational studies. Probability is still viewed as long-run relative frequency, but the emphasis now shifts to conditional probability and independence, basic rules for calculating probabilities of compound events, the Multiplication Rule, probability distributions, and their expected values. Probability is presented as an essential tool for decision making in a world of uncertainty.

(California Mathematics Framework, 2013, p. 635)