Probability Quiz

What is the lecture about?

1. This requires a very specific order, yes to each lecture.
100% chance of one
45% chance of two
70% chance of three
35% chance of four
Multiply those together and you get 11%

3 (going out of order). Likewise, this requires a specific order of events
100% chance of one
55% chance of two (does not give the lecture)
60% chance of three (again, does not give the lecture)
70% chance of four
Multiple those and you get 23%

2: There are three ways to give two lectures, 1-2, 1-3 and 1-4. We've already calculated 1-4 above (which is why I went out of order.) Using the same technique:
1-2 = 100% x 45% x 30% x 30% = 4.1%
1-3 = 100% x 55% x 40% x 30% = 6.6%
All total you are looking at 34%

You should check these as I tossed them off quickly before work.

I think 1-3 should be .55 * .4 * .65 since he gave the third lecture (1-.35).

Gosh, I wish I remembered my Statistics class, but that was over 50 years ago.
I can barely remember something about the bell curve.
Like they say, use it or lose it. I lost it.

Not knowing what the lecture is about negates the question.
Anyone who 'plays-along' with this question, and tries to answer it - Is worthy of sympathy.