Answer:
Step-by-step explanation:
- Refer to the graph attached
1. The mean is calculated using below table
Marks Frequencies Midpoint Product
10 to 14 18 12 216
15 to 19 9 17 153
20 to 24 11 22 242
25 to 29 25 27 675
30 to 34 14 32 448
35 to 39 3 37 111
Sum 80 1845
The mean is:
2. The mode is the midpoint of the tallest bar.
The mode is
3. The median is the middle of the data set. The number of frequencies is 80, the middle frequency is number 40, which is within the 25 to 29 bar.
Formula to calculate median:
- L + ( (n/2 – F) / f ) * w
where
- L: The lower limit of the median group = 25
- n: The total number of observations = 80
- F: The cumulative frequency up to the median group = 18 + 9 + 11 = 38
- f: The frequency of the median group = 25
- w: The width of the median group = 29 - 25 = 4
Substitute values and calculate:
- 25 + ((80/2 - 38)/25) *4 = 25.32
