Normal Steps Coin Probability
1. **Problem 1: Probability of exceeding 13,000 steps**
The number of steps per day is normally distributed with mean $\mu=10000$ and standard deviation $\sigma=1500$.
We want to find the percentage of days the student exceeds 13,000 steps, i.e., $P(X>13000)$.
2. **Formula and approach:**
Use the standard normal distribution $Z=\frac{X-\mu}{\sigma}$.
Calculate the z-score for 13,000 steps:
$$z=\frac{13000-10000}{1500}=\frac{3000}{1500}=2$$
3. **Find the probability:**
From standard normal tables or using symmetry:
$$P(X>13000)=P(Z>2)$$
The area to the right of $z=2$ is approximately 0.0228 or 2.28%.
4. **Interpretation:**
This means the student exceeds 13,000 steps about 2.28% of the days.
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5. **Problem 2: Probability of obtaining two heads and one tail when tossing three coins**
6. **Total outcomes:**
Each coin has 2 outcomes, so total outcomes for 3 coins:
$$2^3=8$$
7. **Favorable outcomes:**
Number of ways to get exactly two heads and one tail is the number of ways to choose which 2 coins are heads:
$$\binom{3}{2}=3$$
8. **Probability:**
$$P=\frac{3}{8}$$
9. **Interpretation:**
The probability of getting exactly two heads and one tail is $\frac{3}{8}$.
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**Final answers:**
- Probability of exceeding 13,000 steps: 2.28%
- Probability of two heads and one tail in three coin tosses: $\frac{3}{8}$