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

1.93

(b)=

P

Z

1.14

(c)=

P

<

0.87

<

Z

2.05

Solution

To solve the probability problems using the standard normal distribution (Z) and rounding to at least three decimal places, we will use standard normal distribution properties and cumulative probabilities:

(a) P(Z>1.93)P(Z > -1.93)

The probability that ZZ is greater than a certain value is equivalent to:

P(Z>1.93)=1P(Z1.93)P(Z > -1.93) = 1 - P(Z \leq -1.93)

Looking up P(Z1.93)P(Z \leq -1.93) from the cumulative distribution table, we get approximately:

P(Z1.93)0.0268P(Z \leq -1.93) \approx 0.0268

So:

P(Z>1.93)=10.0268=0.9732P(Z > -1.93) = 1 - 0.0268 = 0.9732

(b) P(Z1.14)P(Z \leq -1.14)

Looking up the cumulative probability for Z1.14Z \leq -1.14:

P(Z1.14)0.1271P(Z \leq -1.14) \approx 0.1271

(c) P(0.87<Z<2.05)P(0.87 < Z < 2.05)

This is the probability that ZZ lies between two values, and can be calculated as:

P(0.87<Z<2.05)=P(Z<2.05)P(Z0.87)P(0.87 < Z < 2.05) = P(Z < 2.05) - P(Z \leq 0.87)

First, look up the cumulative probabilities:

P(Z2.05)0.9798P(Z \leq 2.05) \approx 0.9798 P(Z0.87)0.8078P(Z \leq 0.87) \approx 0.8078

Now subtract the two:

P(0.87<Z<2.05)=0.97980.8078=0.1720P(0.87 < Z < 2.05) = 0.9798 - 0.8078 = 0.1720

Final answers:

(a) P(Z>1.93)=0.9732P(Z > -1.93) = 0.9732

(b) P(Z1.14)=0.1271P(Z \leq -1.14) = 0.1271

(c) P(0.87<Z<2.05)=0.1720P(0.87 < Z < 2.05) = 0.1720


Do you want more details on these calculations or have any questions?

Here are five related questions to further explore the topic:

  1. What is the probability of Z0Z \leq 0 in the standard normal distribution?
  2. How do you compute P(Z>1.5)P(Z > 1.5) in a standard normal distribution?
  3. What is the symmetry property of the normal distribution that helps simplify these calculations?
  4. How would you calculate P(2<Z<1)P(-2 < Z < 1)?
  5. Can you explain how the standard normal distribution is related to z-scores in real-world data?

Tip: Always remember that probabilities for P(Z>x)P(Z > x) can be computed by subtracting the cumulative probability from 1.

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Math Problem Analysis

Mathematical Concepts

Probability
Statistics
Standard Normal Distribution

Formulas

P(Z > x) = 1 - P(Z ≤ x)
P(a < Z < b) = P(Z < b) - P(Z ≤ a)

Theorems

Cumulative Distribution Function (CDF) of Standard Normal Distribution

Suitable Grade Level

Grades 10-12