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 39 and a standard deviation of 3. using the 68-95-99.7 rule, what is the approximate percentage of lightbulb replacement requests numbering between 39 and 48?
do not enter the percent symbol.
ans = %

50 percent

Step-by-step explanation:

Mean = 39

Using the 68-95-99.7 rule, 68% of the data falls within first  standard deviation of mean

95% data falls within two standard deviation of mean

99.7% data falls within 3 standard deviation of mean

Refer the attached graph

The curve is normally distributed

Now the the percentage of light bulb replacement requests numbering between 39 and 48 = 34%+13.5%+2.5% = 50%

Hence  the approximate percentage of light bulb replacement requests numbering between 39 and 48 is 50 .

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