Clinical Biostatistics: Mouse livers exercise

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Temme et al. (2001) compared two genetic strains of mice, wild-type and connexin32-deficient. They measured the diameters of bile canaliculi in the livers of wild-type and C02-deficient animals, making several observations on each liver.

See detailed description at d. d

Fig. 3. Morphometric analysis of the diameter of bile canaliculi in wild-type and C02-deficient liver. Means±SEM from three livers. *P<0.005

In such papers, authors seldom give details of their statistical methods, so we will assume that they used either a two sample t test or large sample z test for two means for this comparison.

Questions

1. What assumptions would we have to make about the data for these tests. Which one is clearly violated here?

Check suggested answer 1

2. How could they have done a potentially valid two sample test?

Check suggested answer 2

Reference

Temme A, Stiimpel F, Rieber GSEP, Willecke KJK, Ott T. (2001) Dilated bile canaliculi and attenuated decrease of nerve-dependent bile secretion in connexin32-deficient mouse liver. Eur J Physiol 442, 961-966.

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Last updated: 31 July, 2006.