Answer
Mean:
$y ̅ =309~mg/dl$
Median:
$y ̃=292~mg/dl$
Work Step by Step
The new sample: 366 327 274 292 274 230 400
$y ̅ =\frac{∑y_i}{n}=\frac{366+327+274+292+274+230+400}{7}=\frac{309}{7}=309$
Position of the median:
$0.5(n+1)=0.5(7+1)=4$
That is, for a sample of size 7, the median is the value of the fourth observation. In the given sample it is 292.
