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Two Means - Known Variance definitions

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  • Hypothesis Test
    A procedure to assess evidence for a claim about population means using sample data and statistical calculations.
  • Null Hypothesis
    A statement asserting no difference between population means, serving as the default assumption in testing.
  • Alternative Hypothesis
    A statement proposing a difference or specific relationship between population means, opposing the null.
  • Population Standard Deviation
    A known measure of variability within a population, used in calculations for z-tests involving two means.
  • Sample Mean
    An average value calculated from a sample, used to estimate the corresponding population mean.
  • Sample Size
    The number of observations in each group, influencing the reliability and validity of statistical results.
  • Z-Test
    A statistical method for comparing two means when population standard deviations are known, using the z-score.
  • Z-Score
    A value indicating how many standard deviations a sample mean difference is from the hypothesized difference.
  • P-Value
    A probability quantifying the evidence against the null hypothesis, guiding decision-making in hypothesis testing.
  • Significance Level
    A threshold, often denoted by alpha, determining when to reject the null hypothesis based on the p-value.
  • Independent Sample
    A group of observations collected without influence from other samples, ensuring valid statistical inference.
  • Random Sample
    A selection method where each member of the population has an equal chance of being chosen, reducing bias.
  • Normal Distribution
    A bell-shaped probability distribution required for certain statistical tests, especially with smaller sample sizes.
  • Two-Sample Z-Test
    A specific z-test comparing means from two independent samples with known population standard deviations.
  • Alpha
    A preset probability threshold for error, commonly set at 0.05, used to judge statistical significance.