The given information isn’t constant.
Thus, we deduct 0.5 from as far as possible and add 0.5 in the maximum furthest reaches of each class.
Class Class Marks (xi) Frequency (fi) fixi
3.5 – 7.5 5.5 5 27.5
7.5 – 11.5 9.5 4 38
11.5 – 15.5 13.5 9 121.5
15.5 – 19.5 17.5 10 175
![\[\Sigma fi\text{ }=\text{ }28~\sigma fixi\text{ }=\text{ }362\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-aef904a7a4cfb0c4098765efe0fe3745_l3.png "Rendered by QuickLaTeX.com")
Mean,
Accordingly, mean of the given information = 12.93.