Adjusted Class Mark Formula

Which of the following is the CORRECT formula for Adjusted Class Mark after applying the continuity correction to inclusive class intervals?

Primary vs Secondary Data Identification

A researcher surveyed school students to find their favourite film star and published a report. Later, another researcher used this published report for a similar study. For the second researcher, this data is:

Tally Placement for Score 57

If a student scores 57 marks in mathematics, in which class interval is a tally mark placed while constructing a frequency distribution with class intervals of 10?