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Ratio of Means

  • Ronald J. Tallarida
  • Rodney B. Murray

Abstract

It is common to compare the difference of two means as discussed in Procedure 39 (t-test). Sometimes it is desirable to compare the ratio of the means; for example in computing potency ratios. Discussed here is the computation of confidence limits for the ratio of two independent means (mathtype) and(mathtype). The observed ratio is \({{{{\bar x}_1}} \mathord{\left/ {\vphantom {{{{\bar x}_1}} {{{\bar x}_2}}}} \right. \kern-\nulldelimiterspace} {{{\bar x}_2}}}\), where the numerator is derived from N1 values of x and the denominator from N2 values of x. The samples are assumed to be independent and the values x normally distributed. The means \({\bar x_1}\) and \({\bar x_2}\) are also normal with variances V 1 and V 2 and covariance of zero.

Keywords

Standard Deviation Confidence Interval Confidence Limit Computer Screen Individual Sample 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1987

Authors and Affiliations

  • Ronald J. Tallarida
    • 1
  • Rodney B. Murray
    • 2
  1. 1.Department of PharmacologyTemple University School of MedicinePhiladelphiaUSA
  2. 2.Department of PharmacologyBiosearch Inc.PhiladelphiaUSA

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