A statistical examination of two population means. A two-sample t-test examines whether two samples are different and is commonly used when the variances of two normal distributions are unknown and when an experiment uses a small sample size. For example, a t-test could be used to compare the average floor routine score of the U.S. women's Olympic gymnastic team to the average floor routine score of China's women's team.


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The test statistic in the t-test is known as the t-statistic. The t-test looks at the t-statistic, t-distribution and degrees of freedom to determine a p value (probability) that can be used to determine whether the population means differ. The t-test is one of a number of hypothesis tests. To compare three or more variables, statisticians use an analysis of variance (ANOVA). If the sample size is large, they use a z-test. Other hypothesis tests include the chi-square test and f-test.

  1. P-Test

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  2. Population

    The entire pool from which a statistical sample is drawn. The ...
  3. Simple Random Sample

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  4. Z-Test

    A statistical test used to determine whether two population means ...
  5. Sample

    A subset containing the characteristics of a larger population. ...
  6. Sample Selection Bias

    A type of bias caused by choosing non-random data for statistical ...
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