Math Problem Statement

Five males with an X-linked genetic disorder have one child each. The random variable x is the number of children among the five who inherit the X-linked genetic disorder. Determine whether a probability distribution is given. If a probability distribution is given, find its mean and standard deviation. If a probability distribution is not given, identify the requirements that are not satisfied.

Solution

The problem requires determining if the table provided is a probability distribution, and if it is, calculating the mean and standard deviation of the distribution.

Step 1: Checking for a Probability Distribution

For a set of values to represent a valid probability distribution, two conditions must be satisfied:

  1. The probabilities must sum to 1.
  2. Each probability P(x)P(x) must be between 0 and 1 (inclusive).

Let's check these conditions:

  • The probabilities given are: P(0)=0.033,P(1)=0.162,P(2)=0.305,P(3)=0.305,P(4)=0.162,P(5)=0.033P(0) = 0.033, \quad P(1) = 0.162, \quad P(2) = 0.305, \quad P(3) = 0.305, \quad P(4) = 0.162, \quad P(5) = 0.033

  • Summing the probabilities: 0.033+0.162+0.305+0.305+0.162+0.033=1.0000.033 + 0.162 + 0.305 + 0.305 + 0.162 + 0.033 = 1.000 So, the sum of probabilities is 1, which satisfies the first condition.

  • Since all probabilities are between 0 and 1, the second condition is also satisfied.

Therefore, this is a valid probability distribution.


Step 2: Finding the Mean (Expected Value)

The formula for the mean μ\mu of a probability distribution is: μ=[xP(x)]\mu = \sum [x \cdot P(x)] Substitute the values from the table: μ=(00.033)+(10.162)+(20.305)+(30.305)+(40.162)+(50.033)\mu = (0 \cdot 0.033) + (1 \cdot 0.162) + (2 \cdot 0.305) + (3 \cdot 0.305) + (4 \cdot 0.162) + (5 \cdot 0.033) μ=0+0.162+0.61+0.915+0.648+0.165=2.5\mu = 0 + 0.162 + 0.61 + 0.915 + 0.648 + 0.165 = 2.5

Thus, the mean μ=2.5\mu = 2.5.


Step 3: Finding the Standard Deviation

The standard deviation σ\sigma is given by the square root of the variance. The variance σ2\sigma^2 is calculated as: σ2=[(xμ)2P(x)]\sigma^2 = \sum [(x - \mu)^2 \cdot P(x)] First, calculate (xμ)2(x - \mu)^2 for each xx: (x2.5)2=(02.5)2=6.25,(12.5)2=2.25,(22.5)2=0.25(x - 2.5)^2 = (0 - 2.5)^2 = 6.25, \quad (1 - 2.5)^2 = 2.25, \quad (2 - 2.5)^2 = 0.25 (32.5)2=0.25,(42.5)2=2.25,(52.5)2=6.25(3 - 2.5)^2 = 0.25, \quad (4 - 2.5)^2 = 2.25, \quad (5 - 2.5)^2 = 6.25 Now, calculate the variance: σ2=(6.250.033)+(2.250.162)+(0.250.305)+(0.250.305)+(2.250.162)+(6.250.033)\sigma^2 = (6.25 \cdot 0.033) + (2.25 \cdot 0.162) + (0.25 \cdot 0.305) + (0.25 \cdot 0.305) + (2.25 \cdot 0.162) + (6.25 \cdot 0.033) σ2=0.20625+0.3645+0.07625+0.07625+0.3645+0.20625=1.294\sigma^2 = 0.20625 + 0.3645 + 0.07625 + 0.07625 + 0.3645 + 0.20625 = 1.294 Finally, the standard deviation σ\sigma is: σ=1.2941.137\sigma = \sqrt{1.294} \approx 1.137


Summary:

  • Mean (Expected Value): μ=2.5\mu = 2.5
  • Standard Deviation: σ1.137\sigma \approx 1.137

Would you like more details or have any questions?

Here are 5 additional questions to consider:

  1. How does the expected value help in understanding the distribution?
  2. What is the significance of the standard deviation in this context?
  3. Can this distribution be modeled using a binomial distribution? Why or why not?
  4. How would the probabilities change if there were 6 males instead of 5?
  5. What are some real-world applications of probability distributions in genetic studies?

Tip: Always check both conditions (sum of probabilities and individual probability values) when verifying if a set of values forms a valid probability distribution.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability Distribution
Expected Value
Standard Deviation

Formulas

Sum of probabilities = 1
Mean (μ) = Σ [x * P(x)]
Variance (σ²) = Σ [(x - μ)² * P(x)]
Standard Deviation (σ) = sqrt(Variance)

Theorems

Basic Probability Distribution Theorem

Suitable Grade Level

Grades 10-12