7-2 Frequency Distributions

This is the interval between two consecutive upper (or lower) class limits.

• class width

• class boundaries

• midpoints

• frequency

These are used as the border between two consecutive bars in a histogram. They are the intermediate value between an upper class limit and the next lower class limit.

• class limits

• class boundaries

• frequencies

• class marks

Why is this frequency distribution incorrect?

• The fourth class width is different from the others

• There is a zero.

• Classes should overlapped.

Find the midpoints.

• 25.5, 35.5, 45.5, 55.5, 65.5, 75.5

• 20.5, 30.5, 40.5, 50.5, 60.5, 70.5, 80.5

• 21, 31, 41, 51, 61, 71

• 30, 40, 50, 60, 70, 80

Complete the definition:

• class boundaries

• lower class limits

• upper lass limits

• midpoints

Given above are marks obtained by 20 students in Math out of 25 presented in grouped frequency distribution table.

How many classes are in this table?

• 1

• 2

• 3

• 4

Given above are marks obtained by 20 students in Math out of 25.

Identify the class mark/mid-value of the class "11-15"

• 11

• 12

• 13

• 14

Given above are marks obtained by 20 students in Math out of 25, presented in grouped frequency distribution table.

Identify the lower class limit for each class.

• 11, 16, 21

• 15, 20, 25

• 10.5, 15.5, 20.5

• 15.5, 20.5, 25.5

Given above are marks obtained by 20 students in Math out of 25, presented in grouped frequency distribution table.

Identify the upper class limit for each class.

• 11, 16, 21

• 15, 20, 25

• 10.5, 15.1, 20.5

• 15.5, 20.5, 25.5

What is class width of the following frequency distribution?

• 3

• 4

• 5

• 19