Loky do
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Egypt,
2021-10-13 15:06
(51 d 03:12 ago)

Posting: # 22627
Views: 548
 

 statistical test for Bioavailability studies [General Sta­tis­tics]

Dears

If I have a bioavailability study and want to compare its PK results with published data, is there any specific statistical test that could be used to prove there is no significant difference between both results?

Thanks in advance


Edit: Category changed; see also this post #1[Helmut]
Helmut
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Vienna, Austria,
2021-10-14 10:59
(50 d 07:19 ago)

@ Loky do
Posting: # 22628
Views: 416
 

 One-sample t-test

Hi Loky do,

» If I have a bioavailability study and want to compare its PK results with published data, is there any specific statistical test that could be used to prove there is no significant difference between both results?

If you have the subject’s data of the previous study, you could work with log-transformed values and use a paired t-test.
If not, i.e., you have only the mean (\(\small{\mu}\)), you could use a one-sample t-test, where \(\small{t=\frac{\overline{x}-\mu}{s/\sqrt{n}}}\) with \(\small{df=n-1}\).
Example in [image]:

set.seed(1234567)
x <- rnorm(n = 24, mean = 20, sd = 5) # give a vector of your study data instead
summary(x)

   Min. 1st Qu.  Median    Mean 3rd Qu.    Max.
  11.11   16.98   20.09   19.82   23.15   27.71


t.test(x, mu = 20, conf.level = 0.90)

        One Sample t-test

data:  x
t = -0.1917, df = 23, p-value = 0.8497
alternative hypothesis: true mean is not equal to 20
90 percent confidence interval:
 18.25799 21.39151
sample estimates:
mean of x
 19.82475


t.test(x, mu = 25, conf.level = 0.90)

        One Sample t-test

data:  x
t = -5.6612, df = 23, p-value = 9.191e-06
alternative hypothesis: true mean is not equal to 25
90 percent confidence interval:
 18.25799 21.39151
sample estimates:
mean of x
 19.82475


Problems:
  • You have to assume that \(\small{\mu}\) is the true mean without any error. Strong assumption, likely false.
  • Based on normal distributed data. Likely the reported \(\small{\mu}\) is the arithmetic mean. If you have also its standard deviation, you could try to bootstrap values from a lognormal distribution. Not trivial.

Dif-tor heh smusma 🖖
Helmut Schütz
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Loky do
★    

Egypt,
2021-10-18 09:59
(46 d 08:18 ago)

@ Helmut
Posting: # 22633
Views: 339
 

 One-sample t-test

Thanks, Dear Helmut :-)
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