Math Problem Statement

Solve

A home improvement company is interested in whether the customer satisfaction rate is different from the 58% currently claimed. The company sponsored a survey of 179 customers and found that 114 customers were satisfied. What is the test statistic? What is the p-value? Does sufficient evidence exist that the customer satisfaction rate is different than the claim by the company at a significance level of α = 0.01?

Solution

To solve this hypothesis testing problem regarding the customer satisfaction rate, let’s break it down step by step.

Problem Details:

  • Claimed satisfaction rate (p0p_0): 58% or 0.58
  • Sample size (nn): 179
  • Number of satisfied customers (xx): 114
  • Significance level (α\alpha): 0.01

We are tasked to:

  1. Compute the test statistic (zz).
  2. Compute the pp-value.
  3. Determine if there is sufficient evidence to reject the null hypothesis (H0H_0).

Step 1: Formulate the Hypotheses

  • Null hypothesis (H0H_0): p=0.58p = 0.58 (the satisfaction rate is 58%).
  • Alternative hypothesis (HaH_a): p0.58p \neq 0.58 (the satisfaction rate is different).

Step 2: Compute the Test Statistic

The test statistic for a proportion is given by: z=p^p0p0(1p0)nz = \frac{\hat{p} - p_0}{\sqrt{\frac{p_0(1-p_0)}{n}}} Where:

  • p^=xn\hat{p} = \frac{x}{n} is the sample proportion.

Calculate p^\hat{p}:

p^=1141790.63799\hat{p} = \frac{114}{179} \approx 0.63799

Plug into the formula for zz:

z=0.637990.580.58(10.58)179z = \frac{0.63799 - 0.58}{\sqrt{\frac{0.58(1-0.58)}{179}}} z=0.057990.580.42179z = \frac{0.05799}{\sqrt{\frac{0.58 \cdot 0.42}{179}}} z=0.057990.00236270.057990.048611.193z = \frac{0.05799}{\sqrt{0.0023627}} \approx \frac{0.05799}{0.04861} \approx 1.193

So, the test statistic is approximately: z1.19z \approx 1.19


Step 3: Compute the pp-value

This is a two-tailed test, so the pp-value is: p=2P(Z>z)p = 2 \cdot P(Z > |z|) Using a standard normal table or calculator: P(Z>1.19)0.1170P(Z > 1.19) \approx 0.1170 p=20.1170=0.234p = 2 \cdot 0.1170 = 0.234


Step 4: Compare pp-value with α\alpha

  • pp-value 0.234\approx 0.234
  • Significance level α=0.01\alpha = 0.01

Since p>αp > \alpha, we fail to reject the null hypothesis. There is not sufficient evidence to conclude that the satisfaction rate is different from 58%.


Final Answers:

  1. Test statistic (zz): 1.19
  2. pp-value: 0.234
  3. Conclusion: Fail to reject H0H_0. No sufficient evidence to suggest the satisfaction rate is different from 58%.

Would you like a deeper explanation of any of these steps or calculations?
Here are 5 follow-up questions you could explore:

  1. How is the critical value method related to this test?
  2. What would the conclusion be if α=0.05\alpha = 0.05 instead?
  3. How would a one-tailed test differ in this situation?
  4. Can this test be applied to a much smaller sample size? Why or why not?
  5. How does the choice of significance level (α\alpha) affect hypothesis testing?

Tip: Always double-check your pp-value using statistical software or a normal distribution calculator for precise results.

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Hypothesis Testing
Proportions
Significance Testing

Formulas

Test statistic for proportion: z = (p̂ - p₀) / sqrt((p₀(1-p₀))/n)
P-value calculation for two-tailed test: p = 2 * P(Z > |z|)

Theorems

Central Limit Theorem
Properties of the Standard Normal Distribution

Suitable Grade Level

Undergraduate Statistics or AP Statistics