Hypothesis Testing in Business Statistics
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What is the null hypothesis for the fertilizer company's claim about the yield of wheat per hectare?

  • The mean yield is equal to 35 quintals. (correct)
  • The mean yield is greater than 35 quintals.
  • The mean yield is less than 35 quintals.
  • The mean yield is not equal to 35 quintals.
  • At a 1% significance level, what conclusion can be drawn if the sample mean salary of teachers is Birr 9,400?

  • The sample mean is significantly lower than the claimed average.
  • The union's claim can be rejected. (correct)
  • The union's claim can be accepted.
  • There is insufficient evidence to conclude anything.
  • What is the primary role of a null hypothesis in hypothesis testing?

  • To prove a hypothesis definitively true
  • To provide an alternative claim to the tested hypothesis
  • To serve as a default assumption that can be tested for rejection (correct)
  • To represent the researcher's desired outcome
  • Which statement correctly describes a Type I error?

    <p>Rejecting a true null hypothesis (A)</p> Signup and view all the answers

    In the hypothesis testing of the contractor's claim about idle construction workers, what was the sample mean found?

    <p>84 minutes (B)</p> Signup and view all the answers

    What is the population standard deviation used in the teacher salary case?

    <p>Birr 3000 (A)</p> Signup and view all the answers

    What is the significance level used to test the claim about the magazine's readers being college students?

    <p>10% (B)</p> Signup and view all the answers

    What does the alternative hypothesis represent in hypothesis testing?

    <p>The potential change or effect that the researcher aims to demonstrate (A)</p> Signup and view all the answers

    In the example analyzing shoppers' trip times, what was the sample mean shopping trip time observed?

    <p>30 minutes (A)</p> Signup and view all the answers

    In business statistics, why is hypothesis testing crucial?

    <p>It provides a method for determining the likelihood of a hypothesis being valid (B)</p> Signup and view all the answers

    When testing the claim made by the director about typing speed, what is the sample variance found?

    <p>720 (C)</p> Signup and view all the answers

    When setting up a hypothesis test, what must be identified first?

    <p>The population parameter to be tested (D)</p> Signup and view all the answers

    What sample size was used in the testing of the contractor's assumption about idle time?

    <p>25 (C)</p> Signup and view all the answers

    What is the null hypothesis (Ho) when testing the economist's claim about unemployment in Addis?

    <p>P &gt; 0.35 (B)</p> Signup and view all the answers

    For the fertilizer company's yield claim, what was the sample mean yield obtained?

    <p>34 quintals (A)</p> Signup and view all the answers

    Which of the following best describes a Type II error?

    <p>Accepting a null hypothesis that is false (B)</p> Signup and view all the answers

    What is the standard deviation of the sample taken for the supermarket shoppers' trip time?

    <p>10 minutes (A)</p> Signup and view all the answers

    In hypothesis testing, what is typically assumed at the beginning of the process?

    <p>That the null hypothesis is true (B)</p> Signup and view all the answers

    What level of significance was used to test the tire company's claim?

    <p>5% (B)</p> Signup and view all the answers

    Using a significance level of 0.01, what is being tested regarding the primary breakfast beverage for Addis residents?

    <p>If more than 60% prefer tea (C)</p> Signup and view all the answers

    What is the conclusion if the test statistic falls beyond the critical region at a 1% level of significance for the teachers' union case?

    <p>Reject the null hypothesis. (C)</p> Signup and view all the answers

    What is true about the formulation of hypotheses in hypothesis testing?

    <p>The hypotheses should be clearly defined and oppositional (B)</p> Signup and view all the answers

    What is the sample size for the analysis of college students among the magazine's readers?

    <p>200 readers (A)</p> Signup and view all the answers

    Which statistical method is primarily being utilized in the examples presented?

    <p>Hypothesis testing (B)</p> Signup and view all the answers

    What proportion of the sampled population in Addis claimed tea as their primary beverage according to the survey?

    <p>325 out of 500 (A)</p> Signup and view all the answers

    What is a key characteristic of a population parameter that must be understood before hypothesis testing?

    <p>It is a specific measurable characteristic of the population (C)</p> Signup and view all the answers

    What assumption can be made when analyzing the results of a hypothesis test?

    <p>A hypothesis cannot be tested without sample data (D)</p> Signup and view all the answers

    In hypothesis testing, what alternative hypothesis (Ha) is appropriate if we want to know if the unemployment rate exceeds 35%?

    <p>Ha: P &gt; 0.35 (A)</p> Signup and view all the answers

    In the context of hypothesis testing, a 2% level of significance means what about the probability of a Type I error?

    <p>0.02 (A)</p> Signup and view all the answers

    What aspect is being analyzed when querying whether more than 35% of Addis's labor force is unemployed?

    <p>Hypothesis testing about a proportion (B)</p> Signup and view all the answers

    What is the correct interpretation of a Type II error in hypothesis testing?

    <p>Failing to identify a significant effect when one actually exists. (B)</p> Signup and view all the answers

    In Example 2, what are the null and alternative hypotheses regarding mean productivity?

    <p>H₀: μ1 = μ2; H₁: μ1 ≠ μ2 (A)</p> Signup and view all the answers

    What is the null hypothesis for the hotel guest bill scenario?

    <p>The mean guest bill is less than or equal to Birr 400. (D)</p> Signup and view all the answers

    Which of the following hypotheses in Example 3 suggests employee dishonesty?

    <p>H₁: The employees are not honest. (C)</p> Signup and view all the answers

    In hypothesis testing, what does failing to reject the null hypothesis imply?

    <p>There is insufficient evidence to support the alternative hypothesis. (A)</p> Signup and view all the answers

    If a drugstore manager assumes employee honesty but shortages occur, what must be assumed if the opposite hypothesis is accepted?

    <p>Some shortages are due to employee dishonesty. (C)</p> Signup and view all the answers

    For the marketing campaign, what will failing to reject the null hypothesis imply?

    <p>There may be a positive effect on sales, but it remains unproven. (A)</p> Signup and view all the answers

    What does the null hypothesis represent in statistical testing?

    <p>The hypothesis that there is no effect or difference. (B)</p> Signup and view all the answers

    In defining a one-tailed test, which of the following statements is correct?

    <p>It tests for an increase or decrease in one direction only. (B)</p> Signup and view all the answers

    In Example 1, what does the null hypothesis involve regarding tire life claims?

    <p>The mean life of tires is 35,000 miles or less. (B)</p> Signup and view all the answers

    Study Notes

    Hypothesis Testing

    • Hypothesis testing is a statistical method used to evaluate a claim about a population parameter.
    • A hypothesis is an assumption about a population parameter (e.g., population mean, proportion, or variance).
    • The parameter must be identified prior to analysis.
    • In business statistics, a hypothesis is a formal statement about a population parameter which needs to be tested.

    What is a Hypothesis?

    • A hypothesis is an assumption about a population parameter.
    • A parameter is a characteristic of a population (e.g., mean, proportion, variance).
    • The parameter must be identified before conducting an analysis.
    • In business statistics, a hypothesis is a formal statement about a population parameter that is tested.

    Hypothesis Testing Steps

    • State the Hypothesis: Define the null and alternative hypotheses.
      • Null Hypothesis (H₀): This is the default assumption, often that there is no effect or difference.
      • Alternative Hypothesis (H₁): This is the claim to be tested.
    • Set the Significance Level: Determine the acceptable risk of rejecting a true null hypothesis (e.g., 5% or 1%).
    • Collect Data: Gather a relevant sample of data to test the hypothesis.
    • Calculate the Test Statistic: Use an appropriate test statistic (e.g., t-test, z-test, chi-square) based on the collected data and hypotheses.
    • Make a Decision: Compare the calculated test statistic to a critical value, or calculate a p-value.
      • Reject H₀ if the test statistic falls within the rejection region (or if the p-value is less than the significance level).
      • Otherwise, fail to reject H₀.

    Type I and Type II Errors

    • Type I Error (False Positive): Rejecting a true null hypothesis.
    • Type II Error (False Negative): Failing to reject a false null hypothesis.

    One-Tailed and Two-Tailed Tests

    • Two-Tailed Test: The hypothesis about the population parameter is rejected when the sample statistic falls into either tail of the distribution.
    • One-Tailed Test: The hypothesis about the population parameter is rejected when the sample statistic falls into one side (tail) of the distribution.
      • A right-tailed test has rejection in the right tail.
      • A left-tailed test has rejection in the left tail.

    Hypothesis Testing: Population Proportion (p)

    • Similar to testing population means, testing population proportions also follows three types of hypotheses:
      • H₀: p = y
      • H₀: p ≥ y
      • H₀: p ≤ y and their corresponding alternatives Ha: p ≠ y, Ha: p < y, and Ha: p > y.

    Examples of Formulating Hypotheses

    • Example 1: The mean guest bill for a weekend is Birr 400 or less.
      • H₀: μ ≤ 400
      • H₁: μ > 400
    • Example 2: Production workers trained in two different programs—no difference in mean productivity.
      • H₀: μ₁ = μ₂
      • H₁: μ₁ ≠ μ₂
    • Example 3: Employees are honest; no shortages due to dishonesty.
      • H₀: Employees are honest (or no shortages due to dishonesty)
      • H₁: Employees are dishonest (or shortages are due to dishonesty).

    Hypothesis Testing about μ: Population Normal, σ known, n small.

    • (Examples and solutions for testing claims about population means.)

    Hypothesis Testing about μ: Population Normal, σ unknown, n small.

    • (Examples and solutions for testing claims about population means.)

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    Description

    This quiz covers the concepts of hypothesis testing, including the definition of a hypothesis, the process involved in hypothesis testing, and its application in business statistics. Test your understanding of the steps involved in formulating and evaluating hypotheses.

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