Math Problem Statement

Consider a uniform distribution from aequals3 to bequals26.

​(a) Find the probability that x lies between 4 and 18.

​(b) Find the probability that x lies between 5 and 11.

​(c) Find the probability that x lies between 6 and 15.

​(d) Find the probability that x lies between 8 and 19.

Solution

A uniform distribution is defined by a constant probability density function (PDF) between two endpoints, aa and bb. For a continuous uniform distribution, the probability that xx lies between two values x1x_1 and x2x_2 (where ax1<x2ba \leq x_1 < x_2 \leq b) is calculated as the ratio of the interval length to the total length of the distribution.

Given the uniform distribution from a=3a = 3 to b=26b = 26, the PDF is:

f(x)=1ba=1263=123f(x) = \frac{1}{b - a} = \frac{1}{26 - 3} = \frac{1}{23}

The probability that xx lies between two values x1x_1 and x2x_2 is given by:

P(x1xx2)=x2x1baP(x_1 \leq x \leq x_2) = \frac{x_2 - x_1}{b - a}

Let's calculate the probabilities for each part.

(a) Probability that xx lies between 4 and 18:

P(4x18)=184263=1423P(4 \leq x \leq 18) = \frac{18 - 4}{26 - 3} = \frac{14}{23}

(b) Probability that xx lies between 5 and 11:

P(5x11)=115263=623P(5 \leq x \leq 11) = \frac{11 - 5}{26 - 3} = \frac{6}{23}

(c) Probability that xx lies between 6 and 15:

P(6x15)=156263=923P(6 \leq x \leq 15) = \frac{15 - 6}{26 - 3} = \frac{9}{23}

(d) Probability that xx lies between 8 and 19:

P(8x19)=198263=1123P(8 \leq x \leq 19) = \frac{19 - 8}{26 - 3} = \frac{11}{23}

Summary of Results:

  • (a) P(4x18)=1423P(4 \leq x \leq 18) = \frac{14}{23}
  • (b) P(5x11)=623P(5 \leq x \leq 11) = \frac{6}{23}
  • (c) P(6x15)=923P(6 \leq x \leq 15) = \frac{9}{23}
  • (d) P(8x19)=1123P(8 \leq x \leq 19) = \frac{11}{23}

Would you like more details or explanations on these results?

Here are 5 related questions to expand your understanding:

  1. How does the uniform distribution differ from a normal distribution?
  2. What is the cumulative distribution function (CDF) for a uniform distribution?
  3. How do you calculate the expected value for a uniform distribution?
  4. What happens if the interval [a,b][a, b] changes in a uniform distribution?
  5. How can uniform distribution be applied in real-life scenarios like random number generation?

Tip: When dealing with probabilities in uniform distributions, remember that the area under the curve is always evenly distributed, so calculating probabilities is just about finding the proportion of the interval.

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Math Problem Analysis

Mathematical Concepts

Probability
Uniform Distribution

Formulas

Probability for continuous uniform distribution: P(x1 ≤ x ≤ x2) = (x2 - x1) / (b - a)
Probability Density Function (PDF) for uniform distribution: f(x) = 1 / (b - a)

Theorems

Uniform Distribution Theorem

Suitable Grade Level

Grades 10-12