Suppose a room is full of 250 students. Some are members of the chess club, and some are members of the drama club. These are not mutually exclusive: some are members of both (perhaps for a performance of Bergman's The Seventh Seal . There are 50 chess-club students and 60 drama-club students. If we randomly select a student, let C be the event the student is in the chess club, and let D be the event the student is in the drama club.
How many students must be in both the chess club and the drama club in order for C and D to be independent events?

Apsychology student wishes to investigate differences in political opinions between business majors and political science majors at her college. she randomly selects 100 students from the 260 business majors and 100 students from the 180 political science majors. does this sampling plan result in a simple random sample? why or why not? no, because each group of 200 students in the sample does not have the same chance of being selected. yes, because each group of 200 students in the sample has the same chance of being selected. no, because each individual student does not have an equal chance of being selected. yes, because each individual student has the same chance of being selected.

Nina has prepared the following two-column proof below. she is given that ∠oln ≅ ∠lno and she is trying to prove that ol ≅ on. triangle oln, where angle oln is congruent to angle lno step statement reason 1 ∠oln ≅ ∠lno given 2 draw oe as a perpendicular bisector to ln by construction 3 ∠leo ≅ ∠neo transitive property of equality 4 m∠leo = 90° definition of a perpendicular bisector 5 m∠neo = 90° definition of a perpendicular bisector 6 le ≅ en definition of a perpendicular bisector 7 δole ≅ δone side-angle-side (sas) postulate 8 ol ≅ on cpctc nina made two errors in the proof. identify and correct the errors.

Draw a geometric diagram of this scenario using two parallel lines and one transversal. (remember that a transversal is a line which cuts across parallel lines.) label the angles, parallel lines, and transversal as indicated in the diagram above.