How closely do mendel insights into dominant and recessives traits match up with the ratios that punnett calculated in his punnett squares?

Perfectly in theory, except there is chance involved

Explanation:

The Punnet square is a diagram that allows scientists to predict the possible outcomes of the offspring when the genotypes of the parents are known. This is in line with Mendel's principles, and from a theoretical point of view would match up perfectly. However, it all works based on probability.

However, inheritance is always down to chance. Of your parents 2 alleles, you always have 50:50 chance of inheriting one of the allele. Overall, this is what is predicted in punnet squares.

However, think about flipping a coin. There is always 50:50 chance of getting heads, but that doesn't mean it is impossible to flip a coin and get tails 10 x in a row. It is just less likely. So in reality, observations might deviate from the theory.