A geneticist crosses a tomato plant heterozygous for both stem color and leaf shape (PpLlPpLlPpLl) with a double homozygous recessive partner (ppllppllppll).
The genes are hypothesized to assort independently, which predicts a 1:1:1:1 1:1:1:1\,1:1:1:1 phenotypic ratio among the offspring.
Out of 400 offspring collected, the following phenotypes are observed:
Which of the following choices correctly shows the calculated chi-squared (χ2\chi^2χ2) value and the degrees of freedom (dfdfdf) that should be used to test this genetic hypothesis?
χ2=20.50\chi^2 = 20.50χ2=20.50; df=4df = 4df=4
χ2=5.13\chi^2 = 5.13χ2=5.13; df=3df = 3df=3
χ2=20.50\chi^2 = 20.50χ2=20.50; df=3df = 3df=3
χ2=5.13\chi^2 = 5.13χ2=5.13; df=4df = 4df=4
