Math Problem Statement

normal distribution using z table.

  1. find the area to the left of 0.75
  2. find the area to the right of -0.75
  3. find the area to the right of 1.96
  4. find the area in between -0.32 and -1.19
  5. find the area in between 0.5 and 2

Solution

Let's go step-by-step to solve each of these problems using the Z-table (Standard Normal Distribution Table).

1. Find the area to the left of 0.75:

To find the area to the left of Z=0.75Z = 0.75, we can directly look up the value of 0.75 in the Z-table. The Z-table gives the cumulative area from the far left (negative infinity) up to the given Z value.

  • For Z=0.75Z = 0.75, the cumulative area is approximately 0.7734.

So, the area to the left of Z=0.75Z = 0.75 is 0.7734.

2. Find the area to the right of -0.75:

To find the area to the right of Z=0.75Z = -0.75, we can first find the area to the left of Z=0.75Z = -0.75 and subtract it from 1.

  • From the Z-table, the area to the left of Z=0.75Z = -0.75 is approximately 0.2266.

Thus, the area to the right of Z=0.75Z = -0.75 is:

10.2266=0.77341 - 0.2266 = 0.7734

So, the area to the right of Z=0.75Z = -0.75 is 0.7734.

3. Find the area to the right of 1.96:

The area to the right of Z=1.96Z = 1.96 can be found by looking up the area to the left of Z=1.96Z = 1.96 in the Z-table and subtracting it from 1.

  • From the Z-table, the area to the left of Z=1.96Z = 1.96 is approximately 0.9750.

Thus, the area to the right of Z=1.96Z = 1.96 is:

10.9750=0.02501 - 0.9750 = 0.0250

So, the area to the right of Z=1.96Z = 1.96 is 0.0250.

4. Find the area between -0.32 and -1.19:

To find the area between two Z-values, we calculate the area to the left of each Z value and then subtract the smaller area from the larger area.

  • From the Z-table:
    • The area to the left of Z=0.32Z = -0.32 is approximately 0.3745.
    • The area to the left of Z=1.19Z = -1.19 is approximately 0.1170.

The area between Z=0.32Z = -0.32 and Z=1.19Z = -1.19 is:

0.37450.1170=0.25750.3745 - 0.1170 = 0.2575

So, the area between Z=0.32Z = -0.32 and Z=1.19Z = -1.19 is 0.2575.

5. Find the area between 0.5 and 2:

Again, we calculate the area to the left of each Z value and subtract to get the area between the two.

  • From the Z-table:
    • The area to the left of Z=0.5Z = 0.5 is approximately 0.6915.
    • The area to the left of Z=2Z = 2 is approximately 0.9772.

The area between Z=0.5Z = 0.5 and Z=2Z = 2 is:

0.97720.6915=0.28570.9772 - 0.6915 = 0.2857

So, the area between Z=0.5Z = 0.5 and Z=2Z = 2 is 0.2857.


Summary of Answers:

  1. Area to the left of 0.75: 0.7734
  2. Area to the right of -0.75: 0.7734
  3. Area to the right of 1.96: 0.0250
  4. Area between -0.32 and -1.19: 0.2575
  5. Area between 0.5 and 2: 0.2857

Would you like more details on how to interpret these areas? Or do you have any questions?

Related Questions:

  1. How do you calculate the area for a Z-value that is not listed directly in the Z-table?
  2. How does the standard normal distribution apply to real-world problems like in finance or psychology?
  3. What are the properties of a standard normal distribution, and why is it symmetric?
  4. Can you find the Z-score for a given cumulative probability using the inverse Z-table?
  5. What is the significance of the Z-value of 1.96 in hypothesis testing?

Tip:

When using the Z-table, make sure to look at the correct section of the table. The Z-table typically lists values for the Z-score's first two digits (e.g., 0.7 for Z = 0.75) and the second decimal place (0.05 for Z = 0.75). Always double-check your row and column!

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Math Problem Analysis

Mathematical Concepts

Normal Distribution
Z-Score
Cumulative Probability
Area under the Curve

Formulas

Cumulative area to the left of Z: value from Z-table
Area to the right of Z: 1 - cumulative area to the left
Area between two Z-scores: cumulative area for Z1 - cumulative area for Z2

Theorems

Empirical Rule for Normal Distribution
Properties of Standard Normal Distribution

Suitable Grade Level

College Level or Advanced High School (Grades 11-12)