Math Problem Statement

You are conducting a study to see if the proportion of voters who prefer democrats is significantly more than 0.78. Thus you are performing a right-tailed test. Your sample data produce the test statistic z=3.084. Find the p-value accurate to 4 decimal places.

p-value =

Solution

To find the p-value for a right-tailed test with a z-score of 3.084, we need to look up the cumulative probability corresponding to this z-score in the standard normal distribution.

The p-value is the area to the right of the z-score, so we will first find the cumulative probability to the left of z=3.084z = 3.084 and then subtract it from 1.

Using a standard normal table or a calculator:

  • The cumulative probability for z=3.084z = 3.084 is approximately 0.9990.

Thus, the p-value is:

p-value=10.9990=0.0010\text{p-value} = 1 - 0.9990 = 0.0010

So, the p-value is 0.0010.

Would you like a further explanation or have any other questions on this topic?

Related Questions:

  1. How do you interpret the p-value in hypothesis testing?
  2. What is the significance of a z-test in hypothesis testing?
  3. How can you determine the critical value for a right-tailed test?
  4. What happens if the p-value is less than the significance level (α)?
  5. How does the z-test compare to the t-test?

Tip:

When conducting hypothesis tests, always check if the sample size is large enough to justify using a z-test, typically n>30n > 30, or if you are testing proportions, if npnp and n(1p)n(1-p) are both greater than 5.

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Math Problem Analysis

Mathematical Concepts

Hypothesis Testing
Z-Test
Normal Distribution

Formulas

p-value = 1 - P(Z < z)

Theorems

Standard Normal Distribution
Right-tailed Test

Suitable Grade Level

Grades 11-12