Statistics

Consider the following frequency distribution :


.tg {border-collapse:collapse;border-spacing:0;}
.tg td{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;
overflow:hidden;padding:10px 5px;word-break:normal;}
.tg th{border-color:black;border-style:solid;border-width:1px;font-family:Arial, sans-serif;font-size:14px;
font-weight:normal;overflow:hidden;padding:10px 5px;word-break:normal;}
.tg .tg-baqh{text-align:center;vertical-align:top}
.tg .tg-0lax{text-align:left;vertical-align:top}

Class :	0-6	6-12	12-18	18-24	24-30
Frequency :	\(a\)	\(b\)	12	9	5

If mean = \({{309} \over {22}}\) and median = 14, then the value (a \(-\) b)² is equal to _____________.