Game Probability
1. **Stating the problem:**
We have a probability table for the outcomes of a game: win, lose, and draw. The probabilities for win and lose are given as 0.3 and 0.25 respectively, and we need to complete the table by finding the probability of a draw.
2. **Completing the table:**
The sum of all probabilities must be 1 because one of the outcomes must happen.
$$P(\text{win}) + P(\text{lose}) + P(\text{draw}) = 1$$
Given:
$$P(\text{win}) = 0.3, \quad P(\text{lose}) = 0.25$$
So,
$$P(\text{draw}) = 1 - (0.3 + 0.25) = 1 - 0.55 = 0.45$$
3. **Expected number of wins in 120 games:**
The expected number of wins is calculated by multiplying the probability of winning by the total number of games played.
$$\text{Expected wins} = P(\text{win}) \times \text{number of games} = 0.3 \times 120 = 36$$
4. **Estimating D using 1 significant figure:**
Given:
$$D = \frac{\sqrt{1.95 \times 9.92^2}}{8.07}$$
Round each number to 1 significant figure:
- $1.95 \approx 2$
- $9.92 \approx 10$
- $8.07 \approx 8$
Calculate inside the square root:
$$2 \times 10^2 = 2 \times 100 = 200$$
Square root:
$$\sqrt{200} = \sqrt{2 \times 100} = 10 \sqrt{2} \approx 10 \times 1.4 = 14$$
Divide by 8:
$$D \approx \frac{14}{8} = 1.75$$
Rounded to 1 significant figure:
$$D \approx 2$$
**Final answers:**
- Probability of draw: $0.45$
- Expected wins in 120 games: $36$
- Estimated $D$ to 1 significant figure: $2$