Math Problem Statement

Suppose Deidre, a quality assurance specialist at a lab equipment company, wants to determine whether or not the company's two primary manufacturing centers produce test tubes with the same defect rate. She suspects that the rates differ between the manufacturing centers. Deidre plans to run a z-test of the difference of two proportions to test the null hypothesis, H0: pA = pB, against the alternative hypothesis, H1: pA ≠ pB, where pA represents the proportion of defective test tubes produced by Center A and pB represents the proportion of defective test tubes produced by Center B. Compute the P-value for Deidre's z-statistic using either software or a z-distribution table. Provide your answer with precision to at least four decimal places.

Solution

To solve the problem described in the image, we will compute the P-value for Deidre's Z-test. The Z-statistic z=2.11z = 2.11 has already been calculated. Let's determine the correct P-value based on this Z-statistic.


Step-by-Step Solution:

  1. Find the P-value for z=2.11z = 2.11:

    The P-value is determined by finding the area under the standard normal curve beyond z=2.11z = 2.11. Since this is a two-tailed test (based on H1:pApBH_1: p_A \neq p_B), we calculate: P=2P(Z>2.11)P = 2 \cdot P(Z > 2.11)

    Using a standard normal table or statistical software:

    • P(Z>2.11)=1P(Z2.11)P(Z > 2.11) = 1 - P(Z \leq 2.11)
    • From the Z-table, P(Z2.11)0.9826P(Z \leq 2.11) \approx 0.9826
    • Thus, P(Z>2.11)=10.9826=0.0174P(Z > 2.11) = 1 - 0.9826 = 0.0174

    Therefore: P=20.0174=0.0348P = 2 \cdot 0.0174 = 0.0348


Final Answer:

The P-value is: P0.0348P \approx 0.0348


Interpretation:

Since P<α=0.05P < \alpha = 0.05, we reject the null hypothesis H0:pA=pBH_0: p_A = p_B. There is significant evidence to suggest that the defect rates differ between the two manufacturing centers.


Would you like further clarification or an explanation of how to use the Z-table?
Here are 5 related questions for practice:

  1. What is the meaning of a two-tailed hypothesis test in this context?
  2. How would the conclusion change if α=0.01\alpha = 0.01?
  3. How can statistical software be used to find the P-value more efficiently?
  4. Why do we multiply by 2 in a two-tailed test?
  5. What steps would be different if this were a one-tailed test?

Tip: Always double-check your P-value by using both Z-tables and statistical software to ensure accuracy.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Hypothesis testing
Z-tests
Proportions
Two-tailed tests

Formulas

Z = (pA - pB) / √[p̂(1 - p̂)(1/nA + 1/nB)]
P-value = 2 × P(Z > |z|)

Theorems

Central Limit Theorem
Properties of the Standard Normal Distribution

Suitable Grade Level

Undergraduate