Math Problem Statement

Find the percent of the total area under the standard normal curve between z = -1.5 and z = -0.75.

Solution

To find the percent of the total area under the standard normal curve between the z-scores z=1.5z = -1.5 and z=0.75z = -0.75, we need to use the standard normal table provided in the image.

Here’s the step-by-step process:

  1. Find the area for z=1.5z = -1.5:

    • The table shows positive z-scores, but because the normal distribution is symmetric, the area for z=1.5z = -1.5 is the same as the area for z=1.5z = 1.5.
    • From the table, for z=1.5z = 1.5, the area is approximately 0.433.
  2. Find the area for z=0.75z = -0.75:

    • Similarly, the area for z=0.75z = -0.75 is the same as for z=0.75z = 0.75.
    • From the table, for z=0.75z = 0.75, the area is approximately 0.273.
  3. Calculate the difference:

    • The area between z=1.5z = -1.5 and z=0.75z = -0.75 is 0.4330.273=0.1600.433 - 0.273 = 0.160.
  4. Convert to percentage:

    • 0.160×100=16%0.160 \times 100 = 16\%.

Therefore, the percent of the total area under the curve between z=1.5z = -1.5 and z=0.75z = -0.75 is approximately 16%.

Would you like a deeper explanation or have any other questions?

Related Questions:

  1. What is the significance of a z-score in statistics?
  2. How would you find the area under the curve for a range of positive z-scores?
  3. How can the standard normal distribution be applied in real-world scenarios?
  4. What would be the area between z-scores of -2 and 0?
  5. How do you use a z-score table to find probabilities for non-standard normal distributions?

Tip:

Remember that the normal distribution table is symmetrical around zero, allowing you to find areas for negative z-scores by looking up their positive counterparts.

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Math Problem Analysis

Mathematical Concepts

Statistics
Standard Normal Distribution
Z-Scores

Formulas

Area between z-scores = Area(z1) - Area(z2)
Percentage = Area × 100

Theorems

Symmetry of the Normal Distribution

Suitable Grade Level

Grades 10-12