Suppose that human pulse rates for children over 10 and adults are approximately normally distributed with a mean of 78 and standard deviation of 12. Suppose a person over 10 years of age is chosen as random. Answer the the following questions; rounding your answers to 4 decimal places. 1. The probability that the pulse rate of the individual is less than 60 1.83 2. The probability that the pulse rate of the individual is more than 100 0.8996 3. The probability that the pulse rate of the individual is between than 60 and 80 4. The probability that the pulse rate of the individual either is less than 55 or more than 95 97.74
Continuous Probability Distributions
Probability distributions are of two types, which are continuous probability distributions and discrete probability distributions. A continuous probability distribution contains an infinite number of values. For example, if time is infinite: you could count from 0 to a trillion seconds, billion seconds, so on indefinitely. A discrete probability distribution consists of only a countable set of possible values.
Normal Distribution
Suppose we had to design a bathroom weighing scale, how would we decide what should be the range of the weighing machine? Would we take the highest recorded human weight in history and use that as the upper limit for our weighing scale? This may not be a great idea as the sensitivity of the scale would get reduced if the range is too large. At the same time, if we keep the upper limit too low, it may not be usable for a large percentage of the population!
![### Understanding Human Pulse Rate Probabilities
Let's explore the given scenario where human pulse rates for children over 10 and adults are approximately normally distributed. The pulse rates have a mean of 78 and a standard deviation of 12. Given this distribution, we can answer some specific probability questions about an individual's pulse rate.
#### Important Concepts:
- **Normal Distribution:** A type of continuous probability distribution for a real-valued random variable.
- **Mean (μ):** The average of all data points, here it is 78.
- **Standard Deviation (σ):** Measurement of the amount of variation or dispersion, in this case, it is 12.
- **Z-score:** A statistical measurement that describes a value's relationship to the mean of a group of values.
#### Questions and Solutions:
Make sure to round your answers to 4 decimal places.
1. **The probability that the pulse rate of the individual is less than 60:**
\[ P(X < 60) = \boxed{1.83} \]
2. **The probability that the pulse rate of the individual is more than 100:**
\[ P(X > 100) = \boxed{0.8996} \]
3. **The probability that the pulse rate of the individual is between 60 and 80:**
\[ P(60 < X < 80) = \boxed{} \]
4. **The probability that the pulse rate of the individual is either less than 55 or more than 95:**
\[ P(X < 55 \text{ or } X > 95) = \boxed{97.74} \]
### Detailed Explanation for Each Probability:
1. **Less than 60:**
- Convert the pulse rate to a z-score: \( Z = \frac{X - \mu}{\sigma} = \frac{60 - 78}{12} = -1.5 \).
- Use a Z-table to find the probability corresponding to \( Z = -1.5 \).
2. **More than 100:**
- Convert the pulse rate to a z-score: \( Z = \frac{100 - 78}{12} = 1.8333 \).
- Use a Z-table to find the probability corresponding to \( Z = 1.8333 \).
3. **Between 60 and 80:**
- Find the z-score for 60 and 80](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F8b9ab9f7-9bb1-4c74-bf8f-d819b7e596b9%2Ff7186040-1953-415f-8ae4-64755ab327b8%2Fzgvcvb_processed.jpeg&w=3840&q=75)
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