Question

The average mark of candidates in an aptitude test was 128.5 with a standard deviation of
8.2. Three scores extracted from the test are; 148, 102, 152. What is the average of the
extracted scores that are extreme values (outliers)?

Answer 1

Given: The average marks of candidates was 128.5 , standard deviation of 8.2 and three scores extracted from the test are 148, 102 and 152.

To find: What is the average of the  extracted scores that are extreme values (outliers)?

Solution:

• Now we have given that the average marks of candidates in an aptitude test was 128.5, so the mean is 128.5

• We have also given the standard deviation as 8.2

• So the outlier will be out sides then:

                   range = mean ± 3 x standard deviation

                   range = 128.5 ± 8.2 × 3

                   range = 128.5 ± 24.6

• So the range is (103.9 , 153.1)

• Now 102 is not in this range so 102 is outlier.

• So the average of outlier, that is 102 will be 102.

Answer:

                The average of the  extracted scores that are extreme values (outliers) is 102.