Math Problem Statement

The weights of newborn baby boys born at a local hospital are believed to have a normal distribution with a mean weight of 3284 grams and a variance of 454,276. If a newborn baby boy born at the local hospital is randomly selected, find the probability that the weight will be less than 4362 grams. Round your answer to four decimal places.

Solution

To find the probability that a randomly selected newborn baby boy weighs less than 4362 grams, given that the weights follow a normal distribution with a mean and variance, we'll use the Z-score formula and standard normal distribution.

Given dataTo find the probability that a randomly selected newborn baby boy weighs less than 4362 grams, given that the weights follow a normal distribution with a mean and variance, we'll use the Z-score formula and standard normal distribution.

Given

  • Mean weight (μ\mu) = 3284 grams
  • Variance (σ2\sigma^2) = 454,276
  • Standard deviation (σ\sigma) = 454,276=673.99\sqrt{454,276} = 673.99 grams (approx.)
  • Weight to compare = 4362 grams

Step 1: Calculate the Z-score

The Z-score formula is: Z=XμσZ = \frac{X - \mu}{\sigma} Where:

  • XX is the value we want to compare (4362 grams)
  • μ\mu is the mean
  • σ\sigma is the standard deviation

Substitute the values: Z=43623284673.99=1078673.991.598Z = \frac{4362 - 3284}{673.99} = \frac{1078}{673.99} \approx 1.598

Step 2: Find the probability

Now we need to find the probability corresponding to Z=1.598Z = 1.598 using standard normal distribution tables or a calculator.

The cumulative probability for Z=1.598Z = 1.598 is approximately 0.9449.

Conclusion:

The probability that a randomly selected newborn baby boy weighs less than 4362 grams is approximately 0.9449.

Would you like more details or have any questions?


Here are 5 related questions to explore:

  1. What is the probability that a newborn weighs more than 4362 grams?
  2. How would the probability change if the mean weight were 3300 grams?
  3. What is the probability of a baby weighing between 3000 and 4000 grams?
  4. If the standard deviation were larger, how would that affect the probability?
  5. How would you calculate the probability if the distribution wasn't normal?

Tip: For normal distributions, Z-scores help compare any value to the mean in terms of standard deviations.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability
Normal Distribution
Z-Score

Formulas

Z = (X - μ) / σ

Theorems

Properties of Normal Distribution
Z-Score Calculation

Suitable Grade Level

Grades 11-12, College