Enter or import raw data to create descriptive, correlation, and regression statistics. Compare summary statistics, develop confidence intervals, and verify hand calculations. Mean – The mean or average of the numbers in the data set. Statistics that must be calculated: Count – Quantity of numbers in the data set. Using the StatCalc class, write a program that calculates and then displays as output to the console, the following statistics against the set of numbers given below. (This number should be very close to 1.0 the closer, the better.// end class StatCalc. (This is not really a p-value don't use this as a significance test.) Probability of getting exactly the observed table: It tends to agree closely with Yates Chi-Square p-value. (2 times whichever is smallest: left-tail, right-tail, or 0.5) Two-tailed p-value calculated as described in Rosner's book: Right-tailed (to test if the Odds Ratio is significantly greater than 1): Left-tailed (to test if the Odds Ratio is significantly less than 1): This is the p-value produced by SAS, SPSS, R, and other software. If you don't know which Fisher Exact p-value to use, use this one. Two-tailed (to test if the Odds Ratio is significantly different from 1): Type of comparison (Alternate Hypothesis) Some browsers will mis-interpret some numbers entered with leading zeros, and will produce wrong results (with no warning message). Warning: Do not enter cell counts with a leading zero! That is, if a cell count is 34, enter it as 34, not as 034. Make sure that the row and column totals add up correctly. 201-213.Įnter the observed numbers into the four cells below. Journal of Quantitative Criminology, Vol.
The reference used for CI calculation for RIOC is: Relative Improvement Over Chance (RIOC) and Phi as Measures of Predictive Efficiency and Strength of Association in 2 × 2 TablesDavid P. (Pub: British Medical Journal Books, UK 2000) p. Ref: Statistics with Confidence (2 nd Ed.)īy DG Altman et al. Wilson's method is used to find CI for adjusted predictive values. (Pub: Cambridge University Press, Cambridge UK, 1992). This method is also described in Numerical Recipes in C (2nd Ed.) Section 15.6, by William H. Fleiss (Pub: John Wiley & Sons, New York, 1981).
Statistical Methods for Rates and Proportions (2 nd Ed.) Many of these concepts are explained in detail in an onlineĮvidence-based Medicine Glossary or Center for Evidence-based Medicine.įor more information about a particular index, click on the link for that index.Ĭonfidence intervals for the estimated parameters are computed by a general method (based on "constant chi-square boundaries") given in: Other measures of association (contingency coefficient, Cramer's phi coefficient, Yule's Q) Measures of inter-rater reliability (% correct or consistent, mis-classification rate, kappa, Forbes' NMI) The Fisher Exact Test, and other indices relevant to various special kinds of 2-by-2 tables:Īnalysis of risk factors for unfavorable outcomes (odds ratio, relative risk, difference in proportions, absolute and relative reduction in risk, number needed to treat)Īnalysis of the effectiveness of a diagnostic criterion for some condition (sensitivity, specificity, prevalence, pos & neg predictive values, adjusted predictive values, pos & neg likelihood ratios, diagnostic and error odds ratios) It will calculate the Yates-corrected chi-square, the Mantel-Haenszel chi-square, This page computes various statistics from a 2-by-2 table. BMJ Books 2000 JavaStat - 2-way Contingency Table Analysis 2-way Contingency Table Litt.: Statistics with Confidence (2 nd Ed.), Altman et al. The Adjusted Predictive Values is in the Derived Quantities table below. $$PPV=$$ (where sens=Sensitivity, spec=Specificity and prev=Prevalence). Then the predicted values cannot be estimated and you should ignore those values.Īlternatively, when the disease prevalence is known, then the predictive valuesĬan be calculated using the following formula's based on Bayes' theorem If the sample prevalence do not reflect the real prevalence of the disease,
0 kommentar(er)
