Mean=Sum of observationsTotal no. ofobservations.
18=3+21+25+17+x+3+19+x−47.
18×7=2x+84
⇒ 126=2x+84
⇒ 2x=126−84
⇒ 2x=42
⇒ x=21
Thus, the value of ‘x’ is 21.
Now, putting the value of ‘x’ equal to 21 in the given observations.
So, the observations are 3, 21, 25, 17, 24, 19, 17.
Arrange the following observations in ascending order.
So, numbers are 3, 17, 17, 19, 21, 24, 25.
Total number of observations is 7.
Since, n is odd we have to use the formula to calculate the median of the given observations.
median of odd number of data = n+12observations.
Median = 7+12observation.
Median = 4 observation.
Median = 19 ( 4th observation = 19)
Thus, the median of the given observations is 19.