1. **State the problem:** We have a table showing the number of guests in different age groups at a wedding. We need to (a) draw a histogram, (b) find the median age group, (c) find the smallest possible number of guests under 50 years, and (d) estimate the mean age using mid-interval values.
2. **Draw the histogram:**
- The horizontal axis represents age groups: 0-20, 20-40, 40-60, 60-80, 80-100.
- The vertical axis represents the number of guests.
- Draw bars for each age group with heights equal to the number of guests: 9, 58, 42, 27, and 4 respectively.
3. **Find the median age group:**
- Total guests = $9 + 58 + 42 + 27 + 4 = 140$.
- Median position = $\frac{140 + 1}{2} = 70.5$th guest.
- Cumulative guests by age group:
- 0-20: 9
- 20-40: 9 + 58 = 67
- 40-60: 67 + 42 = 109
- The 70.5th guest lies in the 40-60 age group because 67 < 70.5 \leq 109.
4. **Smallest possible number of guests under 50 years:**
- Age groups under 50 years are 0-20 and part of 40-60 (since 40-60 covers 40 to 60).
- Guests in 0-20: 9
- Guests in 20-40: 58 (all under 40, so under 50)
- For 40-60 group (42 guests), only those aged 40 to 50 count.
- The 40-60 group spans 20 years; 40-50 is 10 years, half of the group.
- Assuming uniform distribution, half of 42 = 21 guests are under 50.
- Total under 50 = 9 + 58 + 21 = 88 guests.
5. **Estimate the mean age:**
- Use mid-interval values: 10, 30, 50, 70, 90.
- Multiply mid-interval by number of guests:
- $10 \times 9 = 90$
- $30 \times 58 = 1740$
- $50 \times 42 = 2100$
- $70 \times 27 = 1890$
- $90 \times 4 = 360$
- Sum of products = $90 + 1740 + 2100 + 1890 + 360 = 6180$
- Mean age = $\frac{6180}{140} = 44.142857...$
- Rounded to 1 decimal place: $44.1$ years.
**Final answers:**
- (b) Median age group: 40-60 years.
- (c) Smallest possible number under 50 years: 88 guests.
- (d) Estimated mean age: 44.1 years.
Wedding Age E8C8Ff
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