The Following Table Shows the Results of a Survey of 420

Essay

The following table shows the results of a survey of 420 authors by a (fictitious) publishing company: $$\begin{array} { | l | l | l | l | } \hline & \begin{array} { l } \text { New } \\\text { Authors }\end{array} & \begin{array} { l } \text { Established } \\\text { Authors }\end{array} & \text { Total } \\\hline \text { Successful } & 90 & 10 & 100 \\\hline \text { Unsuccessful } & 150 & 170 & 320 \\\hline \text { Total } & 240 & 180 & 420 \\\hline\end{array}$$ ​
A successful author is chosen at random.
Compute the estimated probability of the event that the successful author is established.