Answer:
(-18,9)
Step-by-step explanation (work shown in picture attached):
1) The first step in solving by substitution is to isolate the y-term in one of the equations if it is not already isolated. Isolate y in the first equation by dividing both sides by -2. This leaves us with the equation
2) Now, substitute
for the y in the second equation. Simplify and isolate x. (You can multiply everything by -2 to get rid of the fraction.) This leaves us with x = -18.
3) We've found the x-value of the solution, -18. Now, substitute -18 for x back into one of the original equations (I chose the first one because it was simple) and isolate y. This gives us y = 9. Thus, in point form, the answer is (-18,9).
Answer:
2.3%
Step-by-step explanation:
The formula to convert x into z distribution is

Where z is the test statistic
x is what we are looking for (in this case 37)
is the mean (in this case, it is 25)
is the standard deviation (we have 6)
<em>Plugging these into the formula, we get:</em>

Thus we can say we want 
<u>Note: </u> 
The table given is for any z where 
Thus, now we have:

0.0228 into percentage is 0.0228 * 100 = 2.28%
Rounded, we get 2.3%
Third answer choice is right.
We can solve this by using the formula:
(x, y) (x + a, y + b) = (5,-4) (-2,1)
So, plugging in the values and solving for a and b,
5 + a = -2
a = -8
-4 + b = 1
b = 5
Therefore, the translation is
(x,y) (x - 8, y +5)
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!
3/20 is 15% so that's bigger