Chi-square analysis of crosses Transitional Reasoning Download PDF

Questions

1. 1.

   A botanist crosses two pink-flowered snapdragons exhibiting incomplete dominance and records 62 red, 92 pink, and 46 white offspring in the F1 generation. Assuming an expected phenotypic ratio of 1:2:1, the researcher performs a chi-square goodness-of-fit test to evaluate the inheritance model at a significance level of 0.05 (critical value = 5.99). Based on this analysis, which evaluation of the data and calculated test statistic is correct?

   • A) The calculated chi-square value is 5.76 with 3 degrees of freedom, indicating that the gene follows a standard Mendelian dominant-recessive inheritance pattern.
   • B) The calculated chi-square value is 1.92 with 1 degree of freedom, indicating significant environmental disruption of floral pigment expression.
   • C) The calculated chi-square value is 7.68 with 2 degrees of freedom, indicating that one of the homozygous phenotypes suffers embryonic lethality.
   • D) The calculated chi-square value is 3.84 with 2 degrees of freedom, indicating that the observed variation from the expected 1:2:1 ratio is due to random chance.