Answer:
d.
Step-by-step explanation:
Hello!
The objective of this test is to know if aerobic exercise modifies hippocampus activity. A random sample of 120 elderly men and women was taken and divided into two groups.
Group 1: Walked around a track three times a week.
Group 2: Did a variety of less aerobic exercises, including yoga and resistance training with bands.
After a year their brains were scanned showing that group 1 had an increase of 2% in their hippocampus and group 2 showed a decrease of 1.4%
a. True, this type of observational study can be the prelude to a more formal statistical study.
b. True, the explanatory variable is "type of exercise", it's the variable that the investigator suspects influence the hippocampus volume.
c. True, the objective of this experiment is to test if there is any modification on hippocampus volume, that's why the volume of the hippocampus was measured, before and after a year of exercise.
d. False, this is an observational study, you cannot establish a causal relationship between the two variables. Just inform you that there seems to be an association. To be able to generalize the results to all elderly population you need a more formal statistical experiment to support your conclusions.
I hope it helps!
The graph is shown in the attached image.
Answer:
142.4 Cubic units
Step-by-step explanation:
V=1/3pir^2h
V=1/3(pi)(4^2)(8.5)
V=142.418866963
Work out the top subtraction first:
3/9 - 8/12
= 1/3 - 2/3
= 1/3
and the bottom part:-
3/8 * 2 = 6/8 = 3/4
so now we divide -1/3 by 3/4
= -1/3 * 4/3 = -4/9
