Computers from a particular company are found to last on average for three years
Computers from a particular company are found to last on average for three years without any hardware malfunction, with a standard deviation of two months. At least what percent of the computers last between 30 months and 42 months? Hints: This is a Chebyshev problem because it doesn't say anything about normal distribution. Step 1: Make sure everything is in the same unit. I suggest months. Step 2: Find how many standard deviations from the mean 30 and 42 are. Step 3: Substitute into Chebyshev's Theorem to find the percentage. (Hopefully you remember and wrote down that k represents the number of standard deviations.)