Math Problem Statement

  1. Find a. �(� < 1.5) b. �(−1.05 < � < 1.5) c. �(� > 1.5)

Solution

To solve these problems, it looks like you are referring to probabilities involving a standard normal distribution, where ZZ represents the standard normal variable (with mean μ=0\mu = 0 and standard deviation σ=1\sigma = 1).

a. P(Z<1.5)P(Z < 1.5)

For a standard normal distribution:

  • We need to find the cumulative probability from -\infty to 1.51.5.
  • This is the value of the cumulative distribution function (CDF) for Z=1.5Z = 1.5.

From standard normal distribution tables or using a calculator, the CDF at Z=1.5Z = 1.5 is:

P(Z<1.5)=0.9332P(Z < 1.5) = 0.9332

b. P(1.05<Z<1.5)P(-1.05 < Z < 1.5)

This is the probability that ZZ lies between 1.05-1.05 and 1.51.5. We calculate this as:

P(1.05<Z<1.5)=P(Z<1.5)P(Z<1.05)P(-1.05 < Z < 1.5) = P(Z < 1.5) - P(Z < -1.05)

From standard normal tables:

  • P(Z<1.5)=0.9332P(Z < 1.5) = 0.9332 (as found above).
  • P(Z<1.05)0.1469P(Z < -1.05) \approx 0.1469.

Thus:

P(1.05<Z<1.5)=0.93320.1469=0.7863P(-1.05 < Z < 1.5) = 0.9332 - 0.1469 = 0.7863

c. P(Z>1.5)P(Z > 1.5)

The probability of ZZ being greater than 1.5 is the complement of P(Z<1.5)P(Z < 1.5):

P(Z>1.5)=1P(Z<1.5)P(Z > 1.5) = 1 - P(Z < 1.5)

Using the result from part (a):

P(Z>1.5)=10.9332=0.0668P(Z > 1.5) = 1 - 0.9332 = 0.0668

Final answers:

  • a. P(Z<1.5)=0.9332P(Z < 1.5) = 0.9332
  • b. P(1.05<Z<1.5)=0.7863P(-1.05 < Z < 1.5) = 0.7863
  • c. P(Z>1.5)=0.0668P(Z > 1.5) = 0.0668

Would you like more details or have any questions on how this was solved?

Here are 5 related questions:

  1. How do you find the area under the normal curve for other values of ZZ?
  2. What is the probability P(Z<1.05)P(Z < -1.05)?
  3. How can we calculate P(Z>1.05)P(Z > -1.05)?
  4. What is the standard normal distribution, and why is it useful?
  5. How can the normal distribution be applied in real-world problems?

Tip: When using standard normal tables, remember that they often provide values for P(Z<z)P(Z < z). To find P(Z>z)P(Z > z), just subtract from 1.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability
Statistics
Standard Normal Distribution

Formulas

P(Z < z) = cumulative distribution function (CDF) of Z
P(a < Z < b) = P(Z < b) - P(Z < a)
P(Z > z) = 1 - P(Z < z)

Theorems

Standard Normal Distribution
Cumulative Distribution Function (CDF)

Suitable Grade Level

Grades 10-12