*Using Chebyshev\'s Inequality* how many times must you toss a fair coin for there to be at least a 90% chance that the ratio of observed tails to total tosses will be between 0.4 and 0.6? Solution Chebyshev\'s inequality, P(|X-u|>k)>1- p^2/k^2 (p^2 is the variance)(u is the mean) So, P(u-k.