Answer:
a) This is an Observational Study because in this kind of study investigators observe subjects and measure variables of interest without assigning treatments to the subjects. Here, the Gilham et al. (2005) studied two different groups where no treatment or intervention was done. These groups were independent of each other.
b) proportions of children with significant social activity in children with acute lymphoblastic leukemia = 1020/1272 = 0.80
proportions of children with significant social activity in children without acute lymphoblastic leukemia = 5343/6238 = 0.86
c) Odds ratio can be calculated using the following formula:
OR= \frac{a/b}{c/d}
where: a - Number in exposed group with positive outcome(here this means number of children with significant social activity associated with acute lymphoblastic leukemia)
b- Number of children without social activity having with acute lymphoblastic leukemia
c- Number of children with social activity having without acute lymphoblastic leukemia
d- Number of children without social activity having without acute lymphoblastic leukemia
OR= \frac{1020/252}{5343/895}
OR= 0.6780
d) The 95% confidence interval of this Odds Ratio is 0.5807 to 0.7917.
e) Since the odds ratio lies in this confidence interval indicate that the amount of social activity is associated with acute lymphoblastic leukemia. The children with more social activity have a higher occurrence of acute lymphoblastic leukemia.
Answer:
The angle of depression from Platform A to Platform B is 
Step-by-step explanation:
Refer the attached figure
The horizontal distance between the platforms is 500 feet i.e. BC = 500
The length of the zip-line is 685 feet i.e. AB = 685
We are supposed to find the angle of depression from Platform A to Platform B
Hypotenuse = 685
Base = 500

Hence the angle of depression from Platform A to Platform B is 
The probability p of an orangecandy is 0.2. The sample size = 100.
The mean is given by:

The standard deviation is given by:

The answers are: Mean = 20. Standard deviation = 4.
-5/2 is the answer. I just took the test and got it right.