Let $y_1, y_2, y_3, \dots, y_n$ be $n$ observations. Let $w_i = l y_i + k$ for all $i = 1, 2, 3, \dots, n$,where $l$ and $k$ are constants. If the mean of $y_i$ is $48$ and their standard deviation is $12$,and the mean of $w_i$ is $55$ and their standard deviation is $15$,then the values of $l$ and $k$ are:
- A$l = 2.5, k = 5$
- B$l = 1.25, k = 5$
- C$l = 1.25, k = -5$
- D$l = 2.5, k = -5$
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