In a test cross that should display a 1: 1: 1: 1 ratio of phenotypes we find 79 for phenotype a, 111 for phenotype b, 85 for phenotype c, and 125 for phenotype d. using a chi square test, what is the probability value (p) for these sample numbers? be careful you use the correct degrees of freedom for 4 categories.

Aresearch study is studying the effects of a new drug for osteoporosis alzheimer's disease (ad) for women above the age of 65 years. a group of individuals with osteoporosis is randomized into two groups. one group is treated conventionally, and the second group is treated with the new medication. assessments are made at 3, 6, 12, 36, and 48 months. the conventionally treated group is assessed for ad using a serum blood test, and the treatment group is assessed for ad using a pet radiotracer that binds to beta-amyloid plaques. in comparing these 2 trial arms, the authors of the study may encounter which type of bias? a. selection bias on the risk of developing b. measurement bias c. confounding bias d. recall bias e. lead-time bias