The physical plant at the main campus of a large state university recieves daily requests to replace florecent lightbulbs.

Question

The physical plant at the main campus of a large state university recieves daily requests to replace florecent lightbulbs. The distribution of the number of daily requests is bell-shaped and has a mean of 59 and a standard deviation of 4. Using the empirical rule (as presented in the book), what is the approximate percentage of lightbulb replacement requests numbering between 51 and 59?

Answer in percent

Answer 1

The probability is the area for the normal standard distribution from -2 to 0 (corresponding to 2 sigma below the mean to the mean.

The 68-95-99.7 rule is an approximation of area (probability in percentage) between ±σ, ±2σ, ±3σ respectively.

The area in question is half of the 2σ range: 95/2 = 47.5%

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