The Life Expectancy of a Fluorescent Light Bulb Is Given

Short Answer

The life expectancy of a fluorescent light bulb is given by the number of hours that it will burn. From the following frequency distribution, find the sample standard deviation of life of this type of bulb.
  $$\begin{array} { | l | l | l | l | } \hline \text { Life of bulb (hours) } & \text { Midpoint } x & \text { Frequency } f & \text { Product } x f \\\hline -0.5 - 499.5 & & 4 & \\\hline 499.5 - 999.5 & & 11 & \\\hline 999.5 - 1,499.5 && 13 & \\\hline 1,499.5 - 1,999.5 && 19 & \\\hline 1,999.5 - 2,499.5 && 28 & \\\hline 2,499.5 - 2,999.5 & & 34 & \\\hline 2,999.5 - 3,499.5 & & 13 & \\\hline 3,499.5 - 3,999.5 & & 3 & \\\hline\end{array}$$ Please round your answer to the nearest whole number, if necessary.
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