How do you determine how many mice to use in an experiment?
Suppose sample size calculated by software is 10 animals per group and researcher is expecting 10% attrition then his final sample size will be 11 animals per group (10/0.9 = 11.11).
Similarly, for 20% attrition sample size should be divided by 0.8..
How do you measure tumor growth in mice?
Two of the most commonly used formulas for determining each individual tumor volume are:
1mg = length (mm) x width2 (mm2) / 2.2volume (V) = length (mm) x width (mm) x depth (mm) x \xcf€/6 (where V is equivalent to mg).How many mice are used for testing?
Over 120 million mice and rats are used annually in research, conventionally housed in shoebox-sized cages that restrict natural behaviours (e.g. nesting and burrowing).
This can reduce physical fitness, impair thermoregulation and reduce welfare (e.g. inducing abnormal stereotypic behaviours)..
How many mice needed for statistical significance?
Most of the time, the sample size is taken for granted, and most scientists use ten mice per group as a rule of thumb.
But scientists should consider determining the sample size for each study based on a scientific rationale..
What are mice used for in research?
In the early days of biomedical research, scientists developed mouse models by selecting and breeding specific mice to produce offspring with certain desired characteristics.
Now scientists use mice to simulate human genetic disorders in order to study their development and test new therapies..
Why are mice always used in experiments?
They can help researchers gain clinical insight due to: Genetic similarity: Mice share common genetic features with humans.
As such, scientists can manipulate the mouse genome, model specific diseases, test new drugs, and investigate the genetics of diseases before trying them on human models..
Why do we use mice for testing?
Humans and mice may not look alike, but almost all the genes in mice share functions with genes in humans.
So, humans and mice get the same diseases for the same reasons.
Every disease has a distinctive set of gene variations, and scientists can study the disease by working with mice with the same genetic profile..
Two of the most commonly used formulas for determining each individual tumor volume are:
1mg = length (mm) x width2 (mm2) / 2.2volume (V) = length (mm) x width (mm) x depth (mm) x \xcf€/6 (where V is equivalent to mg)- Assuming that this “predicted detectable ES” is judged to be acceptable, a sample size of 12 mice per group can be used. “A power analysis shows that the sample size of 12 mice/group has a 90% power to detect an ES of 0.97 n/\xb5l or an 11% change, assuming a 5% significance level and a two-sided test.”
