1. **State the problem:** We want to find the best estimate of the mean number of years of experience of general managers based on the grouped frequency data provided. 2. **Formula used:** The mean for grouped data is calculated using the formula: $$\bar{x} = \frac{\sum f_i x_i}{\sum f_i}$$ where $f_i$ is the frequency of the $i$-th group and $x_i$ is the midpoint of the $i$-th group. 3. **Given data:** | Experience (years) | Frequency ($f_i$) | Midpoint ($x_i$) | |--------------------|------------------|-----------------| | 5.5–8.5 | 3 | 7 | | 8.5–11.5 | 5 | 10 | | 11.5–14.5 | 6 | 13 | | 14.5–17.5 | 12 | 16 | | 17.5–20.5 | 10 | 19 | | 20.5–23.5 | 4 | 22 | 4. **Calculate $f_i x_i$ for each group:** - $3 \times 7 = 21$ - $5 \times 10 = 50$ - $6 \times 13 = 78$ - $12 \times 16 = 192$ - $10 \times 19 = 190$ - $4 \times 22 = 88$ 5. **Sum frequencies and products:** - $\sum f_i = 3 + 5 + 6 + 12 + 10 + 4 = 40$ - $\sum f_i x_i = 21 + 50 + 78 + 192 + 190 + 88 = 619$ 6. **Calculate the mean:** $$\bar{x} = \frac{619}{40} = 15.475$$ 7. **Round to two decimal places:** $$15.48$$ **Final answer:** The best estimate of the mean number of years of experience is **15.48** years.