Math Problem Statement

If 1 male college student is randomly selected, find the probability that he gains between 0 kg and 3 kg during freshman year.

Solution

To solve this problem, we need to calculate the probability that a male college student gains between 0 kg and 3 kg during freshman year. Here’s the plan:

  1. Understand the Normal Distribution:

    • Mean (μ\mu) = 1.3 kg
    • Standard Deviation (σ\sigma) = 4.7 kg
  2. Standardize the Values: Using the Z-score formula: Z=XμσZ = \frac{X - \mu}{\sigma}

    • For X=0X = 0 kg: Z0=01.34.7=0.2766Z_0 = \frac{0 - 1.3}{4.7} = -0.2766
    • For X=3X = 3 kg: Z3=31.34.7=0.3617Z_3 = \frac{3 - 1.3}{4.7} = 0.3617
  3. Find the Probabilities Corresponding to the Z-Scores: Using the Z-table or a statistical calculator:

    • For Z0=0.2766Z_0 = -0.2766: P(Z<0.2766)0.3910P(Z < -0.2766) \approx 0.3910
    • For Z3=0.3617Z_3 = 0.3617: P(Z<0.3617)0.6410P(Z < 0.3617) \approx 0.6410
  4. Calculate the Desired Probability: The probability of gaining between 0 kg and 3 kg is: P(0X3)=P(Z<0.3617)P(Z<0.2766)P(0 \leq X \leq 3) = P(Z < 0.3617) - P(Z < -0.2766) P(0X3)=0.64100.3910=0.2500P(0 \leq X \leq 3) = 0.6410 - 0.3910 = 0.2500

Final Answer:

The probability is 0.2500.


Would you like a step-by-step explanation of any part of this process? Here are some related questions to expand on this topic:

  1. How do you find probabilities for values outside a certain range in a normal distribution?
  2. What is the purpose of standardizing values with Z-scores?
  3. How does the shape of the normal distribution affect probabilities?
  4. What is the cumulative distribution function (CDF) for a normal distribution?
  5. Can you calculate probabilities using a calculator instead of a Z-table?

Tip: Always check if the data follows a normal distribution before applying these methods.

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Math Problem Analysis

Mathematical Concepts

Normal Distribution
Probability
Z-scores

Formulas

Z = (X - μ) / σ
P(a ≤ X ≤ b) = P(Z ≤ Z_b) - P(Z ≤ Z_a)

Theorems

Properties of the Normal Distribution

Suitable Grade Level

College-level or Advanced High School