Math Problem Statement

Suppose Z follows the standard normal distribution. Calculate the following probabilities using the ALEKS calculator. Round your responses to at least three decimal places.

(a) P(z > 2.00) =

(b) P(z <= 1.44) =

(c) P(- 1.09 < Z < 2.20) =

Solution

Let's calculate each of the probabilities based on the standard normal distribution ZZ, where ZZ has a mean μ=0\mu = 0 and standard deviation σ=1\sigma = 1. We'll use the cumulative distribution function (CDF) of the standard normal distribution.

(a) P(Z>2.00)P(Z > 2.00)

  • To find this probability, we calculate P(Z>2.00)P(Z > 2.00). Using the CDF for Z=2.00Z = 2.00, we find the area to the left of 2.00 and subtract it from 1.

    P(Z2.00)0.9772P(Z \leq 2.00) \approx 0.9772 Therefore, P(Z>2.00)=10.9772=0.0228P(Z > 2.00) = 1 - 0.9772 = 0.0228

    Answer: P(Z>2.00)0.023P(Z > 2.00) \approx 0.023

(b) P(Z1.44)P(Z \leq 1.44)

  • Here, we need the cumulative probability for Z1.44Z \leq 1.44.

    P(Z1.44)0.9251P(Z \leq 1.44) \approx 0.9251

    Answer: P(Z1.44)0.925P(Z \leq 1.44) \approx 0.925

(c) P(1.09<Z<2.20)P(-1.09 < Z < 2.20)

  • This is the probability that ZZ lies between 1.09-1.09 and 2.202.20. We calculate:

    P(Z2.20)0.9861P(Z \leq 2.20) \approx 0.9861 P(Z1.09)0.1379P(Z \leq -1.09) \approx 0.1379 Therefore, P(1.09<Z<2.20)=0.98610.1379=0.8482P(-1.09 < Z < 2.20) = 0.9861 - 0.1379 = 0.8482

    Answer: P(1.09<Z<2.20)0.848P(-1.09 < Z < 2.20) \approx 0.848

Let me know if you'd like further details on these calculations or have any questions!


Here are 8 related questions you might find interesting:

  1. What is P(Z>1.96)P(Z > 1.96)?
  2. How do you calculate P(Z<1.64)P(Z < -1.64)?
  3. What is the probability that ZZ lies between 0 and 2.33?
  4. How do you interpret a z-score of 3.0 in terms of probability?
  5. What is P(0.5<Z<0.5)P(-0.5 < Z < 0.5)?
  6. How do you find the area under the curve to the right of Z=1.5Z = -1.5?
  7. What is the 90th percentile of the standard normal distribution?
  8. How do you standardize a variable to calculate probabilities?

Tip: Always remember that the total area under the standard normal curve equals 1, so probabilities for values outside a given range can often be easily calculated by subtracting from 1.

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Math Problem Analysis

Mathematical Concepts

Normal Distribution
Standard Normal Distribution
Cumulative Distribution Function (CDF)

Formulas

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Theorems

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Suitable Grade Level

Undergraduate