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 x-axis represents age groups: 0-20, 20-40, 40-60, 60-80, 80-100.
- The y-axis represents the number of guests, from 0 to 70 in steps of 10.
- Bars heights correspond to the number of guests: 9, 58, 42, 27, 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 counts:
- Up to 0-20: 9
- Up to 20-40: $9 + 58 = 67$
- Up to 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:**
- Guests under 50 include all in 0-20 and 20-40 groups plus some in 40-60 group.
- Number in 0-20 and 20-40 = $9 + 58 = 67$.
- The 40-60 group has 42 guests.
- Since 50 is halfway in 40-60, the smallest number under 50 is if all guests from 40-60 are aged 50 or above except the minimum needed to reach 50.
- To find how many guests are under 50, note that 50 is halfway in 40-60, so half of 42 = 21 guests could be under 50.
- So smallest possible number under 50 = $67 + 0 = 67$ if none in 40-60 are under 50, but since median is in 40-60, at least some must be under 50.
- More precisely, since median is 70.5th guest and cumulative up to 20-40 is 67, the 3.5 guests into 40-60 group are under 50.
- So smallest possible number under 50 = $67 + 3.5 = 70.5$ guests.
5. **Estimate mean age using mid-interval values:**
- Mid-intervals: 0-20: 10, 20-40: 30, 40-60: 50, 60-80: 70, 80-100: 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: 70.5 guests.
- (d) Estimated mean age: 44.1 years.
Wedding Ages 409762
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