\(\begin{array}{c|c}& 4th\ grade & 5th\ grade & 6th\ grade &Total \\ \hline Grades &49&50&69&168\\ \text{Athletic} &24&36&38&98\\ \text{Popular}\ &19&22&28&69\\ \hline \text{Total} & 92 & 108 & 135 &335 \end{array}\)

The table contains data of 335 students, which is given in the bottom right corner of the given table.

\(\text{# of possible outcomes} = 335\)

All students who are 6th grades and rated good grades as important are given in the row "6th grade” or in the column ”Grades” of the given table. Adding all corresponding counts, we then note that this corresponds with 49+50+69+38 +28=211 students who are 6th graders or rated good grades as important.

\(\text{# of favorable outcomes} = 234\)

The probability is the number of favorable outcomes divided by the number of possible outcomes:

\(P(\text{ 6th grade or Grades})=\frac{\text{# of favorable outcomes}}{\text{# of possible outcomes}}\)

\(=\frac{234}{335}\)

\(\approx 0.6985\)

\(=69.85\%\)