Math Problem Statement

Given the below cumulative distribution function, find the following probabilities. CDF: F(x) = 0 if x <2 0.2 if 2≤x<3 0.25 if 3 ≤x <6 0.35 if 6≤x<9 1 if 9≤x P(X = 0)= 0 P(X< 3) = 0.25 P(X < 6) = P(6 ≤ X <9)= P(2 < X ≤6)= P(2 < X< 9)= P(X ≥3)= P(X > 6) = 0.65 く 0.65 0.15 0.15

Solution

Let's go through the given cumulative distribution function (CDF) and compute the probabilities requested. Here's a breakdown of the given CDF F(x)F(x):

  • F(x)=0F(x) = 0 if x<2x < 2
  • F(x)=0.2F(x) = 0.2 if 2x<32 \leq x < 3
  • F(x)=0.25F(x) = 0.25 if 3x<63 \leq x < 6
  • F(x)=0.35F(x) = 0.35 if 6x<96 \leq x < 9
  • F(x)=1F(x) = 1 if x9x \geq 9

Now, we'll compute the requested probabilities:

  1. P(X=0)P(X = 0):

    • Since the CDF shows F(x)=0F(x) = 0 for x<2x < 2, and X=0X = 0 falls in this range, the probability is: P(X=0)=0P(X = 0) = 0
  2. P(X<3)P(X < 3):

    • From the CDF, for x=3x = 3, F(x)=0.25F(x) = 0.25. Since the CDF is non-decreasing, and for x<3x < 3, F(x)=0.2F(x) = 0.2, the probability of P(X<3)P(X < 3) is: P(X<3)=0.2P(X < 3) = 0.2
  3. P(X<6)P(X < 6):

    • From the CDF, for x=6x = 6, F(x)=0.35F(x) = 0.35. Thus, the probability of P(X<6)P(X < 6) is: P(X<6)=0.25P(X < 6) = 0.25
  4. P(6X<9)P(6 \leq X < 9):

    • From the CDF, the probability mass between 6 and 9 can be found by subtracting the values of the CDF at these points: P(6X<9)=F(9)F(6)=10.35=0.65P(6 \leq X < 9) = F(9) - F(6) = 1 - 0.35 = 0.65
  5. P(2<X6)P(2 < X \leq 6):

    • The probability between 2 and 6 is: P(2<X6)=F(6)F(2)=0.250.2=0.05P(2 < X \leq 6) = F(6) - F(2) = 0.25 - 0.2 = 0.05
  6. P(2<X<9)P(2 < X < 9):

    • The probability between 2 and 9 is: P(2<X<9)=F(9)F(2)=10.2=0.8P(2 < X < 9) = F(9) - F(2) = 1 - 0.2 = 0.8
  7. P(X3)P(X \geq 3):

    • This can be found as: P(X3)=1P(X<3)=10.2=0.8P(X \geq 3) = 1 - P(X < 3) = 1 - 0.2 = 0.8
  8. P(X>6)P(X > 6):

    • The probability for X>6X > 6 is: P(X>6)=1F(6)=10.35=0.65P(X > 6) = 1 - F(6) = 1 - 0.35 = 0.65

Summary of Results:

  • P(X=0)=0P(X = 0) = 0
  • P(X<3)=0.2P(X < 3) = 0.2
  • P(X<6)=0.25P(X < 6) = 0.25
  • P(6X<9)=0.65P(6 \leq X < 9) = 0.65
  • P(2<X6)=0.05P(2 < X \leq 6) = 0.05
  • P(2<X<9)=0.8P(2 < X < 9) = 0.8
  • P(X3)=0.8P(X \geq 3) = 0.8
  • P(X>6)=0.65P(X > 6) = 0.65

Do you need further details on any of these probabilities?


Related Questions:

  1. What is the total probability for the entire distribution?
  2. How would P(X=2)P(X = 2) and P(X=6)P(X = 6) be determined?
  3. What is the probability that X=9X = 9?
  4. How does the CDF help in finding probabilities of ranges like P(aXb)P(a \leq X \leq b)?
  5. What is the significance of jumps in the CDF for discrete distributions?

Tip: The probability for a single value in a continuous distribution is always zero unless the distribution has discrete components at that point.

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Math Problem Analysis

Mathematical Concepts

Cumulative Distribution Function (CDF)
Probability

Formulas

P(X < b) = F(b)
P(a ≤ X < b) = F(b) - F(a)
P(X ≥ a) = 1 - F(a)

Theorems

Properties of Cumulative Distribution Functions

Suitable Grade Level

College Level - Statistics