STA215H5 Lecture 7: stats unit 4
Document Summary
Unit 4 is all about probability, but before we get into it we should understand how to count up cases of interest: at so(cid:373)e poi(cid:374)t (cid:455)ou (cid:373)a(cid:455) (cid:272)o(cid:374)du(cid:272)t a(cid:374) e(cid:454)peri(cid:373)e(cid:374)t a(cid:374)d need to account for all possible cases/outcomes. By the end of this set of slides you should be able to: 1. distinguish which formulae is appropriate based on a word problem. 2. identify the variables in each formula based on a word problem. 3. plug into each formula and calculate the value based on a word problem. Multiplication rule: uppose (cid:455)ou ha(cid:448)e (cid:374) disti(cid:374)(cid:272)t o(cid:271)je(cid:272)ts, a(cid:374)d the(cid:455) are partitioned into k groups, with niobjects per group, you (cid:449)a(cid:374)t to sele(cid:272)t o(cid:374)e o(cid:271)je(cid:272)t fro(cid:373) ea(cid:272)h group. Ho(cid:449) many ways can this be done? (cid:374)(cid:1005)(cid:454) (cid:374)(cid:1006)(cid:454) (cid:374)(cid:1007)(cid:454) (cid:454) (cid:374)k. Symbolically a factorial is an exclamation point (!) = n x (n-1) x (n-(cid:1006)) (cid:454) . (cid:454) (cid:1007) (cid:454) (cid:1006) (cid:454) (cid:1005)
