GradeGen

A measure of how likely an outcome is, expressed as a fraction, decimal or percentage.

These are probabilities, not guarantees. Four offspring need not include exactly three tall plants and one short plant; each fertilisation is a new chance event. The simple square also applies only to the single-gene characteristic being modelled.

The likelihood that an outcome will occur, expressed as a fraction, decimal or percentage.

The chance of an outcome occurring, expressed as a fraction, decimal or percentage.

A numerical measure of how likely an outcome is, from 0 for impossible to 1 for certain.

A genetic cross therefore predicts the probability of each possible offspring genotype rather than stating which offspring will definitely be produced.

A probability predicts a chance for each offspring, not an exact number in a small family.

Treat the genetic cross as a probability model. It does not predict the sex of a particular child or guarantee equal numbers in a small family.

State whether a ratio or probability refers to genotypes or phenotypes; these may differ.