Math Problem Statement

1.For a standard normal variable Z, which of the following z values satisfies the expression: P(Z > z) = 0.57

Solution

To find the value of zz for which P(Z>z)=0.57P(Z > z) = 0.57, we can use the standard normal distribution table (also known as the Z-table) or the cumulative distribution function (CDF) of the standard normal distribution.

Step-by-Step Solution:

  1. Understand the problem:

    • P(Z>z)=0.57P(Z > z) = 0.57 means that the probability that the standard normal variable ZZ is greater than zz is 0.57.
  2. Translate to cumulative probability:

    • The cumulative distribution function (CDF) gives P(Zz)P(Z \leq z), which is the area to the left of zz.
    • Since the total probability is 1, we have: P(Zz)=1P(Z>z)=10.57=0.43P(Z \leq z) = 1 - P(Z > z) = 1 - 0.57 = 0.43
    • So, we need to find zz such that P(Zz)=0.43P(Z \leq z) = 0.43.
  3. Find the corresponding z-value:

    • Using a standard normal distribution table or a calculator, find the zz-value that corresponds to a cumulative probability of 0.43.
    • Looking it up, z0.18z \approx -0.18.

Final Answer:

The value of zz that satisfies P(Z>z)=0.57P(Z > z) = 0.57 is approximately z0.18z \approx -0.18.

Would you like a more detailed explanation, or do you have any questions?

Here are some related questions you might find helpful:

  1. What is the standard normal distribution?
  2. How do you interpret a Z-score?
  3. How do you use the Z-table to find probabilities?
  4. What is the cumulative distribution function (CDF)?
  5. How would you find the probability P(Z<z)P(Z < z) for a given z-value?
  6. How do you calculate the probability between two Z-scores?
  7. How do you find Z-scores that correspond to specific probabilities without a Z-table?
  8. What are some applications of Z-scores in real-life scenarios?

Tip: Remember that for standard normal distribution, negative Z-scores indicate values below the mean, and positive Z-scores indicate values above the mean.

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Math Problem Analysis

Mathematical Concepts

Statistics
Probability
Normal Distribution

Formulas

Cumulative Distribution Function (CDF) of the Standard Normal Distribution

Theorems

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Suitable Grade Level

Advanced High School