# Thread: Chi square Dominant phenotype problem

1. ## Chi square Dominant phenotype problem

What is the ChiSquare value for the dominant phentotype of the cross Purple versus White. Should the answers be 696.75 or 696?? Neither are correcct

Parental Phenotypes

Purple X White

F1 Phenotype

All Purple

F2 Phenotype

705 purple, 224 white

I must be missing something:

Observed Purple=705

Observed White= 224

Total 929

Expected for Purple 705/929=.75

.75x929= 696.75 Purple Expected

Expected White 224/929=.24

.24 x 929= 222.96 White Expected

Second part of the question is

What is the Chi Square Sum (rounding to 3 significant figures) for Purple versus White cross. 0.391 How did they get 0.391?

But when I try to get this answer I use the formula (O-E)^2/E and get .09768 for Purple and .0048 for White which equals .1085

Third part of the question:

Using the following web site: (http://www.graphpad.com/quickcalcs/PValue1.cfm)
What is the P-value (rounding to 3 significant figures) for Purple versus White cross.