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α

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Intro to Statistics

Definition

α (alpha) is the significance level in hypothesis testing, representing the probability of rejecting the null hypothesis when it is actually true. Commonly set at 0.05, it indicates a 5% risk of Type I error.

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5 Must Know Facts For Your Next Test

  1. Alpha (α) represents the threshold for statistical significance in hypothesis testing.
  2. A common alpha value used in many tests is 0.05, but it can vary depending on the study's requirements.
  3. Choosing a smaller alpha reduces the risk of Type I error but increases the risk of Type II error.
  4. If the p-value is less than or equal to α, you reject the null hypothesis.
  5. Alpha is a predetermined value set before conducting the test and is not influenced by sample data.

Review Questions

  • What does α represent in hypothesis testing?
  • How does changing α affect Type I and Type II errors?
  • Why must α be set before conducting a statistical test?
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