Fish Frequency 20989C
1. **Problem statement:** Given the frequency table of fish caught:
Number of fish: 0, 1, 2, 3, 4, 5, 6
Frequency: 6, 20, 45, 70, 35, 10, 2
Calculate:
i) Mean number of fish caught
ii) Modal number of fish caught
iii) Median number of fish caught
iv) Range in the number of fish caught
2. **Formulas and rules:**
- Mean: $$\text{mean} = \frac{\sum (x \times f)}{\sum f}$$ where $x$ is the number of fish and $f$ is the frequency.
- Mode: The value of $x$ with the highest frequency.
- Median: The middle value when data is ordered; find the cumulative frequency and locate the middle position.
- Range: $$\text{range} = \text{max value} - \text{min value}$$
3. **Calculations:**
- Total frequency: $$6 + 20 + 45 + 70 + 35 + 10 + 2 = 188$$
- Calculate $\sum (x \times f)$:
$$0 \times 6 = 0$$
$$1 \times 20 = 20$$
$$2 \times 45 = 90$$
$$3 \times 70 = 210$$
$$4 \times 35 = 140$$
$$5 \times 10 = 50$$
$$6 \times 2 = 12$$
Sum: $$0 + 20 + 90 + 210 + 140 + 50 + 12 = 522$$
- Mean:
$$\frac{522}{188} \approx 2.7766$$
- Mode:
Highest frequency is 70 at number of fish = 3, so mode = 3.
- Median:
Total frequency = 188, so median position = $$\frac{188 + 1}{2} = 94.5$$th value.
Cumulative frequencies:
0 fish: 6
1 fish: 6 + 20 = 26
2 fish: 26 + 45 = 71
3 fish: 71 + 70 = 141
Since 94.5 lies between 71 and 141, median number of fish = 3.
- Range:
Max number of fish = 6, Min number = 0
Range = $$6 - 0 = 6$$
4. **Assumption for part b:**
The rate of fish caught per hour remains constant over the next four hours as it was in the first two hours.
**Final answers:**
i) Mean = 2.78 (rounded to 2 decimal places)
ii) Mode = 3
iii) Median = 3
iv) Range = 6
Assumption: The catch rate is constant over time.