Math Problem Statement

A sports league performs a hypothesis test at the 0.10 level of significance to determine if the proportion, p, of all times a certain referee’s coin comes up heads is different from 50%. The null hypothesis (H0) is p = 0.5, and the alternative hypothesis (H1) is p ≠ 0.5. The problem requires completing a Type I and Type II error table, performing a Z-test, determining whether to reject or not reject the null hypothesis, and identifying if the conclusion is correct if the true proportion is 50%.

Solution

Let's break down the information given and solve the questions one by one.

Problem Overview

  1. Hypotheses:

    • Null Hypothesis (H0H_0): p=0.5p = 0.5
    • Alternative Hypothesis (H1H_1): p0.5p \neq 0.5
  2. Significance Level: α=0.10\alpha = 0.10 (indicating a 10% significance level)

  3. Test Statistic: The Z-test is used, with the test statistic value given as z=1.195z = -1.195.

Part (a): Decision Table for Type I and Type II Errors

The table in part (a) requires us to classify the result of the test as correct, a Type I error, or a Type II error based on whether we reject or do not reject H0H_0 and the true nature of H0H_0.

  1. Type I Error: Rejecting H0H_0 when H0H_0 is actually true.
  2. Type II Error: Failing to reject H0H_0 when H0H_0 is actually false.
  3. Correct Decision: Either rejecting H0H_0 when it’s false or not rejecting H0H_0 when it’s true.

Using this information, you can fill out the table as follows:

  • Reject H0H_0 when H0H_0 is true: Type I Error
  • Reject H0H_0 when H0H_0 is false: Correct Decision
  • Do not reject H0H_0 when H0H_0 is true: Correct Decision
  • Do not reject H0H_0 when H0H_0 is false: Type II Error

Part (b): Z-Test P-Value Calculation

The Z-test statistic is z=1.195z = -1.195. For a two-tailed test:

  1. Find the p-value: Using a Z-table, find the p-value associated with z=1.195z = -1.195 and double it because this is a two-tailed test.

    • For z=1.195z = -1.195, the one-tailed p-value is approximately 0.116.
    • For a two-tailed test, the p-value is 2×0.116=0.2322 \times 0.116 = 0.232.
  2. Decision based on p-value: Since 0.232>0.100.232 > 0.10, we do not reject H0H_0 at the 10% significance level.

You can shade the central area under the normal curve (symmetrically around zero) up to 1.195-1.195 and 1.1951.195 to represent the p-value.

Part (c): Conclusion for Hypothesis Test

Based on the p-value (0.232), which is greater than the significance level (0.10), the result is:

  • Do not reject the null hypothesis.

Part (d): Interpreting the Result (Type I or Type II Error)

If the true proportion is 50%, then H0H_0 is true. By not rejecting H0H_0, the decision is correct, not an error.

The answer to (d) is:

  • The result is correct.

Do you need more details or have any questions?

Follow-Up Questions

  1. Can you explain why we use a two-tailed test instead of a one-tailed test here?
  2. How would the result change if the significance level were set to 5% instead of 10%?
  3. What is the difference between a Type I and a Type II error in this context?
  4. How is the p-value calculated from the z-score in hypothesis testing?
  5. What would be the interpretation if the p-value were less than the significance level?

Tip:

Remember, in hypothesis testing, always check if the test is one-tailed or two-tailed, as this impacts how you calculate and interpret the p-value.

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Math Problem Analysis

Mathematical Concepts

Hypothesis testing
Z-test
Type I and Type II errors
Significance level

Formulas

p-value calculation for Z-test

Theorems

Null hypothesis significance testing (NHST)

Suitable Grade Level

College Level