Hypothesis Testing in Statistics
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Questions and Answers

What is a hypothesis?

A hypothesis is a tentative statement that explains facts about a situation based on available evidence.

What is the purpose of hypothesis testing?

Hypothesis testing is a statistical procedure used to resolve a hypothesis.

What are the two main types of hypotheses?

  • True and False
  • Sample and Population
  • Null and Alternative (correct)
  • Directional and Nondirectional
  • What is the difference between a null hypothesis and an alternative hypothesis?

    <p>The null hypothesis, denoted by H0, states that there is no difference between a parameter and a specific value. The alternative hypothesis, denoted by Ha, states that there is a difference between a parameter and a specific value. It is the opposite or the negation of the null hypothesis.</p> Signup and view all the answers

    Explain the concept of a rejection region in hypothesis testing.

    <p>The rejection region is the interval in the sampling distribution that leads to the rejection of the null hypothesis. It is determined based on the significance level chosen for the test.</p> Signup and view all the answers

    A directional test involves a comparison where the alternative hypothesis is expressed as 'less than' (<) or 'greater than' (>).

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

    A nondirectional test involves a comparison where the alternative hypothesis is expressed as 'not equal to' (≠).

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

    What is a Type I error? (Select all that apply)

    <p>Also known as alpha error (α error) (C), Rejecting the null hypothesis when it is true (D)</p> Signup and view all the answers

    Flashcards

    Hypothesis

    A tentative statement explaining facts, based on available evidence.

    Hypothesis Testing

    A statistical method to test the validity of a hypothesis.

    Null Hypothesis (H₀)

    A statement assuming no difference between a parameter and a specific value.

    Alternative Hypothesis (Hₐ)

    A statement claiming a difference between a parameter and a specific value.

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    Parameter

    A numerical characteristic of a population.

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    Sample Mean (X̄)

    An estimate of the population mean, calculated from a sample.

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    Population Mean (μ)

    The average value of a characteristic within an entire population.

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    Z-test

    A statistical test used when population variance is known and sample size is large (n > 30).

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    Directional Test

    A hypothesis test with an alternative hypothesis implying a specific direction (e.g., greater than or less than).

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    Non-directional test

    A hypothesis test with an alternative hypothesis implying a difference without specifying direction (e.g., not equal to).

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    Type I error

    Rejecting a true null hypothesis.

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    Type II error

    Accepting a false null hypothesis.

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    Level of Significance

    The probability of committing a Type I error (denoted by α).

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    Rejection Region

    The range of test statistics that leads to rejecting the null hypothesis.

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    Standard Deviation (σ)

    A measure of the amount of variation or dispersion of a set of values.

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    Sample size (n)

    The total number of observations included in a sample.

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    T-test

    Statistical test used for small sample sizes and unknown population variance (n < 30).

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    Chi-Square Test

    Statistical test used to analyze categorical data and assess if observed frequencies match expected frequencies.

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    Scatter Plot

    A graph showing the relationship between two variables.

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    Study Notes

    Hypothesis Testing

    • Hypotheses are tentative statements explaining facts based on available evidence.
    • Hypothesis testing is a statistical procedure to validate a hypothesis.
    • A statistical hypothesis is a statement about a population parameter.
    • Null hypothesis (H₀) states no difference or no relationship.
    • Alternative hypothesis (Hₐ) states a difference or a relationship.

    Two Kinds of Hypotheses

    • Null Hypothesis (H₀): A statement that there is no difference between a parameter and a specific value.
    • Alternative Hypothesis (Hₐ): A statement that there exists a difference between a parameter and a specific value, or the negation of the null hypothesis.

    Types of Tests and Rejection Regions

    • Directional test (One-tailed): A test with an alternative hypothesis expressing less than (<) or greater than (>) is directional. Rejection region is on one side of the distribution.
    • Nondirectional test (Two-tailed): A test with an alternative hypothesis expressed as not equal to (≠) is non-directional. Rejection region is on both sides of the distribution.

    Types of Errors

    • Type I error (α error): Rejecting the null hypothesis when it's true.
    • Type II error (β error): Accepting the null hypothesis when it's false.

    Level of Significance

    • The probability of committing a Type I error. It's symbolized by α (alpha).

    Parameters and Their Symbols

    • Mean (μ): The average of outcomes in a process or experiment.
    • Variance (σ²): A measure of variability of a data set.
    • Standard deviation (σ): The square root of variance, indicating average distance of observed values from the mean.

    Test Statistic Formulas (z-test/t-test)

    • Z-test formula is used when the population variance is known and the sample size (n) is greater than or equal to 30. Z = (X - μ) / (σ / √n) where: X = sample mean μ = population mean σ = population standard deviation n = sample size

    • t-test formula is used when the population variance is unknown with sample size less than 30. t = (X - μ) / (s / √n) where: X = sample mean μ = population mean s = sample standard deviation n = sample size df = n - 1

    Scatter Plots

    • Scatter plots are diagrams showing the relationships between two sets of data. Plotting data points on a graph displays a trend.

    • Variables are labeled with independent (X-axis), and dependent (Y-axis), values.

    • A scatter plot can show correlation between variables.

    Pearson's Correlation Coefficient (r)

    • r: A numerical value from -1 to +1 representing the strength and direction of correlation between variables. Values close to ±1 indicate strong correlation.

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    Description

    This quiz explores the fundamentals of hypothesis testing, including the definitions and differences between null and alternative hypotheses. It also covers types of tests and rejection regions in statistical analysis. Test your knowledge on the critical concepts of hypothesis testing.

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