Math Problem Statement

Assume that a randomly selected subject is given a bone density test. The test scores are normally distributed with a mean of 0 and a standard deviation of 1. Find the probability of a bone density test score greater than -1.76.

Solution

The problem involves a normally distributed variable with a mean of 0 and a standard deviation of 1, and it asks to find the probability of a bone density test score being greater than -1.76.

The correct region to sketch on the normal curve for a probability of a score greater than -1.76 would be the right tail of the distribution, starting at -1.76 and extending to infinity. Option A shows this correctly, where the shaded region represents the area to the right of -1.76, corresponding to the probability of a score greater than -1.76.

Now, let's calculate the probability:

  1. We need to find the z-score corresponding to -1.76. This is given directly as the z-score, since the distribution has a mean of 0 and a standard deviation of 1.
  2. Using a standard normal table or a calculator, the cumulative probability up to -1.76 is approximately 0.0392.
  3. Since we are interested in the probability greater than -1.76, we subtract this from 1: P(X>1.76)=1P(X1.76)=10.0392=0.9608P(X > -1.76) = 1 - P(X \leq -1.76) = 1 - 0.0392 = 0.9608

Thus, the probability is 0.9608.

Would you like further clarification, or do you have any additional questions?

Here are five related questions to explore:

  1. What is the probability of a score greater than 1.76 in a normal distribution?
  2. How do you calculate probabilities for values between two z-scores, for example, between -1.76 and 1.76?
  3. How does the area under the normal curve change with different standard deviations?
  4. What is the total area under the normal distribution curve, and why is it significant?
  5. Can you explain the symmetry of the normal distribution and how it affects probability calculations?

Tip: When solving normal distribution problems, it is always useful to check if you're dealing with a "greater than" or "less than" probability to apply the correct cumulative probability subtraction.

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Math Problem Analysis

Mathematical Concepts

Normal Distribution
Probability
Z-Scores

Formulas

Cumulative probability formula for Z-scores
P(X > z) = 1 - P(X ≤ z)

Theorems

Empirical Rule (68-95-99.7 Rule)
Properties of the Standard Normal Distribution

Suitable Grade Level

College or Advanced High School Statistics