Biol 300 Assignment 7 Chapter 14 Q22.
(a) No control group.
(b) The control was not simultaneous⎯time is a confounding variable.
(c) Treatments were not assigned randomly to patients. Sex is a confounding variable.
(d) This study failed to include blinding (best is double blind, in which neither patients
nor clinician knows which subjects received which treatment).
Extra question:
H0: Mean amount of nectar doesn’t differ among caffeine concentrations. HA: Mean
amount of nectar differs among caffeine concentrations.
Source Sum of Squares df
Mean Squares F
Groups
1.1344
3
0.3781
Error
1.4482
16
0.0905
Total
2.5826
19
4.18
𝐹!.!" ! ,!,!" = 3.24. Since F > 3.24, P < 0.05. Reject H0 (P = 0.023). Caffeine
concentration does affect mean amount of nectar taken.