The frequency distribution table shows the number of mango trees in a grove and their yield of mangoes. Find the median of the data:
| No. of Mangoes | No. of Trees (f) |
|---|---|
| 50 – 100 | 33 |
| 100 – 150 | 30 |
| 150 – 200 | 90 |
| 200 – 250 | 80 |
| 250 – 300 | 17 |
Step 1: Find the cumulative frequency (c.f.).
| Class Interval | Frequency (f) | Cumulative Frequency (c.f.) |
|---|---|---|
| 50 - 100 | 33 | 33 |
| 100 - 150 | 30 | 63 |
| 150 - 200 | 90 | 153 |
| 200 - 250 | 80 | 233 |
| 250 - 300 | 17 | 250 |
Step 2: Find total frequency.
N = 250
Step 3: Find median class.
N/2 = 250 / 2 = 125
The c.f. just greater than 125 is 153. Hence, the median class is 150 - 200.
Step 4: Apply the median formula.
Median = L + ((N/2 - c.f.) / f) × h
Where:
L = 150, N = 250, c.f. = 63, f = 90, h = 50
Substitute the values:
Median = 150 + ((125 - 63) / 90) × 50
= 150 + (62 / 90 × 50)
= 150 + 34.44 = 184.44
Step 5: Conclusion.
The median number of mangoes produced per tree is approximately 184.4.
Final Answer: Median = 184.4
Let the Mean and Variance of five observations $ x_i $, $ i = 1, 2, 3, 4, 5 $ be 5 and 10 respectively. If three observations are $ x_1 = 1, x_2 = 3, x_3 = a $ and $ x_4 = 7, x_5 = b $ with $ a>b $, then the Variance of the observations $ n + x_n $ for $ n = 1, 2, 3, 4, 5 $ is
Find the variance of the following frequency distribution:
| Class Interval | ||||
| 0--4 | 4--8 | 8--12 | 12--16 | |
| Frequency | 1 | 2 | 2 | 1 |