Answer: Lower quartile = 19 and Upper quartile = 38.
Explanation:
Since we have given that
15, 19, 20, 25, 31, 38, 41
Since they are arranged in increasing order.
We need to calculate the upper and lower quartile of this data set:
Number of data = 7
which is an odd number.
We have to divide it into lower half and upper half excluding the central value to calculate lower and upper quartile.
Since central value = 25
So, Lower half includes : 15,19,20
Upper half includes : 31,38,41.
So, Median of lower half is known as lower quartile.
Median of upper half is known as upper quartile.
Hence, Lower quartile = 19
Upper quartile = 38.