Question

The following table shows data during a 1hr exam for a student.

$$\begin{array}{cc}\text{Time during exam(mins)}& \text{Total number of questions solved in the exam}\\ 0-10& 2\\ 10-20& 5\\ 20-30& 10\\ 30-40& 15\\ 40-50& 17\\ 50-60& 25\end{array}$$

Plot the less than type ogive curve

• A.
• B.
• C.
• D.

Answer 1

The correct option is A

The table contains the time wise number of questions solved by a student in 1hr . The total number of questions solved as given in the table is the cumulative frequency of the number of questions and not the frequency which can be understood from the data points and the mention of the word ‘TOTAL’. In 0-10 mins of the exam , a student solved 2 questions. In 10-20 mins of the exam he/she solved 5 questions which implies that he/she solved 3 questions in next 10 mins of the exam.

$$\begin{array}{cc}\text{Time}& \text{Total number of questions}\\ <10& 2\\ <20& 5\\ <30& 10\\ <40& 15\\ <50& 17\\ <60& 25\end{array}$$

The data points are (10,2) , (20,5) , (30,10) ,(40,15) , (50,17) , (60,25)

For determining median draw a horizontal line at $\frac{n}{2}$ = 12.5. From the point where the line meets the curve , draw a vertical line to meet x axis. The point where the line meets the x axis is the median.