January 2017
Beginner
882 pages
203h 41m
English
1. Stock splits occur at the sudden drops. You could verify this by finding out the number of Pfizer shares being trading on the stock market.
3. Yes, this is simple variation.
Bell shaped.
A 6% drop is z = (− 6.0 − 1.45)/7.30 ≈ 1 SDs below the mean. From the Empirical Rule, the chance is about ½ × 1/3 = 1/6. In the data, 122 such events occur out of 862 months, or 122/862 ≈ 0.142, or about 14%.
1.45 − 2 × 7.30 = − 13.15%, so the VaR is 1,000 × 0.1315 = $131.50. That's the most that could be lost, ruling out the worst 2.5% of occurrences.