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  2. Sample ratio mismatch - Wikipedia

    en.wikipedia.org/wiki/Sample_ratio_mismatch

    Sample ratio mismatches can be detected using a chi-squared test. [3] Using methods to detect SRM can help non-experts avoid making discussions using biased data. [4] If the sample size is large enough, even a small discrepancy between the observed and expected group sizes can invalidate the results of an experiment. [5] [6]

  3. Sample size determination - Wikipedia

    en.wikipedia.org/wiki/Sample_size_determination

    The table shown on the right can be used in a two-sample t-test to estimate the sample sizes of an experimental group and a control group that are of equal size, that is, the total number of individuals in the trial is twice that of the number given, and the desired significance level is 0.05. [4]

  4. Engine balance - Wikipedia

    en.wikipedia.org/wiki/Engine_balance

    The shape could be enclosed in a 5 ⁄ 8-inch square for one of the unbalanced locomotives and was reduced to a point when weights were added to counter revolving and reciprocating masses. [12] The effect of vertical out-of-balance, or varying wheel load on the rail, was quantified by Professor Robinson in the U.S. in 1895.

  5. Ground and neutral - Wikipedia

    en.wikipedia.org/wiki/Ground_and_neutral

    The neutral carries current if the loads on each phase are not identical. In some jurisdictions, the neutral is allowed to be reduced in size if no unbalanced current flow is expected. If the neutral is smaller than the phase conductors, it can be overloaded if a large unbalanced load occurs.

  6. PS Power and Sample Size - Wikipedia

    en.wikipedia.org/wiki/PS_Power_and_Sample_Size

    Matched or independent study designs may be used. Power, sample size, and the detectable alternative hypothesis are interrelated. The user specifies any two of these three quantities and the program derives the third. A description of each calculation, written in English, is generated and may be copied into the user's documents.

  7. Tukey's range test - Wikipedia

    en.wikipedia.org/wiki/Tukey's_range_test

    The value q s is the sample's test statistic. (The notation | x | means the absolute value of x; the magnitude of x with the sign set to +, regardless of the original sign of x.) This q s test statistic can then be compared to a q value for the chosen significance level α from a table of the studentized range distribution.

  8. Panel data - Wikipedia

    en.wikipedia.org/wiki/Panel_data

    An unbalanced panel (e.g., the second dataset above) is a dataset in which at least one panel member is not observed every period. Therefore, if an unbalanced panel contains N {\displaystyle N} panel members and T {\displaystyle T} periods, then the following strict inequality holds for the number of observations ( n {\displaystyle n} ) in the ...

  9. PASS Sample Size Software - Wikipedia

    en.wikipedia.org/wiki/PASS_Sample_Size_Software

    PASS is a computer program for estimating sample size or determining the power of a statistical test or confidence interval. NCSS LLC is the company that produces PASS. NCSS LLC also produces NCSS (for statistical analysis). PASS includes over 920 documented sample size and power procedures.