The table below shows the distribution of quiz scores for a class of students: | Score Interval | Frequency (f) | |---|---| | 1 - 5 | 3 | | 6 - 10 | 5 | | 11 - 15 | 7 | | 16 - 20 | 5 | Calculate the mean score of the distribution.

The table below shows the distribution of quiz scores for a class of students: | Score Int… — JAMB UTME

The table below shows the distribution of quiz scores for a class of students:

Calculate the mean score of the distribution.

Cevap: 11.5

The mean score of the distribution is 11.5.

The mean for a grouped frequency table is calculated by taking the sum of the products of each midpoint (

x

) and its frequency (

f

), divided by the sum of all frequencies (

f

). Here,

\sum fx = 230

and

\sum f = 20

, yielding

\bar{x} = 11.5

Determine the class midpoints (

x

) for each interval.

Midpoints are 3, 8, 13, and 18.

Midpoints serve as the representative values for each class interval.

Calculate the product of each midpoint and frequency (

fx

Products are 9, 40, 91, and 90.

To find the total contribution of each class interval.

Find the sum of all frequencies (

\sum f

) and products (

\sum fx

\sum f = 20

and

\sum fx = 230

These totals are required for the grouped mean formula.

Divide the total product sum by total frequency.

\bar{x} = \frac{230}{20} = 11.5

Applying the formula for the mean of grouped data

\bar{x} = \frac{\sum fx}{\sum f}

Mean of Grouped Data using Class Midpoints