Replicates and repeats

The authors of this paper were interested to see whether the expression of three proteins (A, B and C) was altered in a knockout mouse model of a gene encoding Protein X. Each experiment measured the expression of a different protein and the results seem to show a clear increase in protein expression in the mutant mouse compared with the control. The results are reported as statistically significant, with impressive ‘n’ values in each condition: the authors say that n = 7 in each case. They confidently conclude that the level of each of the three proteins is increased in the knockout mutant.