CALCULATION OF

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					                         CALCULATION OF
        GEOMETRIC MEAN CUT-OFF CONCENTRATION
            OF SCHIZONT MATURATION (GMCOC)


EXAMPLE: ARTEMISININ, MAE HONG SON, 1994

No.of      CUT-OFF CONCENTRATION (nM)
ISOL.
           30      100       300       1000      3000

 51         1       11         15        23          1

log     1.4771 22.0000 37.1568       69.0000   3.4771


log for all 51 isolates = 133.1110

log/n = log GMCOC = 2.61002

GMCOC = antilog 2.61002 = 407.40 (nM)

SD (to log GMCOC) = 0.44478

SE (to log GMCOC) = 0.06228

95 % CI for GMCOC is 305.82 to 542.73 (nM)
EXAMPLES: ARTEMISININ, MAE HONG SON (MHS) 1994 & 1999

            ARTEMISININ, MAE SOT (MS) 2000


AREA   No. of     CUT-OFF CONCENTRATION OF SM (nM)
& YEAR ISOL.
                   30      100       300        1000        3000


MHS 94     51       1       11        15          23           1

MHS 99     35      13       16            6        0           0

MS 2000    37       8       17            5        6           1


                logGMCOC         SD                 SE

MHS 1994         2.61002         0.44478          0.06228

MHS 1999         1.88758         0.36290          0.06134

MS 2000          2.15351         0.54353          0.08936


                GMCOC (nM)       95 % CI for GMCOC (nM)

MHS 1994         407.40               305.82 to 542.73

MHS 1999          77.19                   58.20 to 102.39

MS 2000          142.40                   94.36 to 214.90


MHS 1994 vs MHS 1999         t = 7.9576       N’ = 84    p < 10-9

MHS 1999 vs MS 2000          t = 2.2153       N’ = 70    p < 0.05
                    COMPARISON OF REGRESSIONS


FOR PARALLELITY:

When SR < fSR the regressions are parallel
When SR > fSR the regressions are not parallel (precluding PR
calculation)

SR = S1 / S2 where S1 is the greater

fSR = antilog [(log fs1)2 + (log fs2)2]0.5




FOR SIGNIFICANT DIFFERENCE OF EFFICACY:

Power Ratio PR > fPR Factor of Power Ratio

PREC-50 = EC50-1 / EC50-2 where EC50-1 is the greater

fPR-50 = antilog [(log fEC50-1)2 + (log fEC50-2)2]0.5


The same procedure can be applied at EC90, EC95 and EC99 levels
using the corresponding EC and fEC values (from computer
output).