Dataset -  3567x34Mean of the data set is given as 5 Wh

SOLUTION

Sum of the observations in the dataset $=3+5+6+7+x+3+4=x+28$

Mean = $\frac{\text{Sum of Observations}}{\text{Number of Observation}}$
 
$\Rightarrow 5=\frac{x+28}{7}$
$\Rightarrow 35-28=x$
$\Rightarrow x=7$