Probability and genetic crosses

Question 1

What is a ratio

Answer 1

A measure of relative size of two groups that is expressed as a proportion

In biology, the ratio is always given as x:1 so you divide the left by the right
Eg 7:5 would be 7/5:1

Question 2

Why are actual results if genetic crosses rarely the same as predicted results

Eg Mendel never got an exact 3:1 ratio for the green:yellow pea pods resulting from the previous offspring

Answer 2

Due to statistical error because each event is independent of the previous,

So it is chance that determines which gametes fuse with which

A way to improve the results is to use a larger sample size so the actual results are more similar to theoretical ones