Homework Stats 8Dd8F7
1. **State the problem:**
We have a set of homework marks: 5, 6, 7, 8 with frequencies 1, 3, 1, and 5 respectively.
We need to find:
(i) the range
(ii) the mode
(iii) the median
(iv) the mean
2. **Recall formulas and definitions:**
- Range = maximum value - minimum value
- Mode = value with highest frequency
- Median = middle value when data is ordered
- Mean = sum of all values divided by total number of values
3. **Calculate total number of data points:**
Total frequency = 1 + 3 + 1 + 5 = 10
4. **Calculate the range:**
Range = max mark - min mark = 8 - 5 = 3
5. **Find the mode:**
The highest frequency is 5 for mark 8, so mode = 8
6. **Find the median:**
Order the data points:
- One 5
- Three 6's
- One 7
- Five 8's
Positions 1 to 10:
1:5
2-4:6
5:7
6-10:8
Median position = $\frac{10+1}{2} = 5.5$, so median is average of 5th and 6th values.
5th value = 7
6th value = 8
Median = $\frac{7 + 8}{2} = 7.5$
7. **Calculate the mean:**
Sum = $5\times1 + 6\times3 + 7\times1 + 8\times5 = 5 + 18 + 7 + 40 = 70$
Mean = $\frac{70}{10} = 7$
**Final answers:**
(i) Range = 3
(ii) Mode = 8
(iii) Median = 7.5
(iv) Mean = 7