Instruction 18-4
a Manufacturer of Computer Disks Took Samples of 240

Instruction 18-4
A manufacturer of computer disks took samples of 240 disks on 15 consecutive days.The number of disks with bad sectors was determined for each of these samples.The results are in the table that follows.
$$\begin{array} { r c c } \text { Day } & \text { Bad } & \% \text { Bad } \\\hline 1 & 9 & 0.037500 \\2 & 7 & 0.029167 \\3 & 4 & 0.016667 \\4 & 6 & 0.025000 \\5 & 8 & 0.033333 \\6 & 3 & 0.012500 \\7 & 6 & 0.025000 \\8 & 10 & 0.041667 \\9 & 16 & 0.066667 \\10 & 24 & 0.100000 \\11 & 15 & 0.062500 \\12 & 9 & 0.037500 \\13 & 4 & 0.016667 \\14 & 8 & 0.033333 \\15 & 6 & 0.025000\end{array}$$
-Referring to Instruction 18-4,the best estimate of the mean proportion of disks with bad sectors is ________.