The subject "Probability methods in engineering" was taken by 100 students. The marks obtained by students in the subject are summarized in the table given below.

Marks in Probability 30-50 50-60 60-70 70-80 80-100

Number of students 4 17 52 21 6

Find.

i. The mean no of marks obtained.

ii. The upper quartile, lower quartile and Inter quartile range.

Draw

iii. A suitable histogram of the data

iv. A Box and Whisker plot of the data.