Math Problem Statement

Please mark f(x) is nothing but the pmf p(x) in the following table. The table shows the probability distribution of a certain computer malfunctioning 0 to 6 times on any given day. Solve for the mean, standard deviation, and various probabilities based on the distribution.

Solution

In the table provided, f(x)f(x) represents the probability mass function (pmf) p(x)p(x) of a random variable XX, which denotes the number of computer malfunctions on a given day. So, you can interpret f(x)=p(x)f(x) = p(x) as follows:

  • xx is the number of malfunctions (ranging from 0 to 6).
  • f(x)f(x) gives the probability of having exactly xx malfunctions.

For example:

  • f(0)=0.17f(0) = 0.17 means there is a 17% chance that there will be 0 malfunctions.
  • f(1)=0.29f(1) = 0.29 means there is a 29% chance that there will be 1 malfunction, and so on.

Now, let’s address the individual parts:

(a) Mean (μ\mu): The mean of the probability distribution can be calculated using the formula:

μ=xxf(x)\mu = \sum_x x \cdot f(x)

(b) Standard deviation (σ\sigma): The standard deviation is calculated as:

σ=x(xμ)2f(x)\sigma = \sqrt{\sum_x (x - \mu)^2 \cdot f(x)}

(c) At most 2 malfunctions: Find P(X2)P(X \leq 2):

P(X2)=f(0)+f(1)+f(2)P(X \leq 2) = f(0) + f(1) + f(2)

(d) More than 3 malfunctions: Find P(X>3)P(X > 3):

P(X>3)=f(4)+f(5)+f(6)P(X > 3) = f(4) + f(5) + f(6)

(e) Exactly 3 malfunctions: This is simply f(3)f(3).

(f) Between 2 and 5 malfunctions (inclusive): Find P(2X5)P(2 \leq X \leq 5):

P(2X5)=f(2)+f(3)+f(4)+f(5)P(2 \leq X \leq 5) = f(2) + f(3) + f(4) + f(5)

Would you like me to calculate any of these values for you?


Here are 5 follow-up questions you might want to consider:

  1. What is the process for calculating the mean for a probability distribution?
  2. How can we interpret the standard deviation in the context of this malfunction data?
  3. How is the cumulative probability calculated for part (c)?
  4. Why do we sum probabilities when calculating P(X2)P(X \leq 2) or P(2X5)P(2 \leq X \leq 5)?
  5. How could this malfunction probability distribution help in computer maintenance planning?

Tip: The sum of all probabilities in a probability mass function must always equal 1.

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Math Problem Analysis

Mathematical Concepts

Probability Mass Function (PMF)
Mean (Expected Value)
Standard Deviation
Cumulative Probability

Formulas

Mean (μ) = Σ(x * f(x))
Standard Deviation (σ) = √(Σ((x - μ)^2 * f(x)))
P(X ≤ 2) = f(0) + f(1) + f(2)
P(X > 3) = f(4) + f(5) + f(6)
P(2 ≤ X ≤ 5) = f(2) + f(3) + f(4) + f(5)

Theorems

Law of Total Probability
Concept of Expected Value

Suitable Grade Level

College Level / Advanced High School