Answer:
Cluster Sampling
Step-by-step explanation:
I cant be 100% sure as i am not in statistics, but by definition cluster sampling is a probability sampling technique where researchers divide the population into multiple groups (clusters) for research (in this case its the phone book). Researchers then select random groups (three random pages) with a simple random or systematic random sampling technique for data collection and data analysis(interviews).
so that appears to be what is happening in this scenario.
Answer:
(-4,2)
Step-by-step explanation:
First we have to find a common multiple to use to add and find the system of equations. We need to eliminate one of the variables in order to solve.
Since 5 * 3 = 15, and 3 * -5 = 15, -15x and 15x will cancel each other out. Therefore x will be eliminated.
Before:
5x + 2y = -16
3x + 7y = 2
After:
15x + 6y = -48 <----------Now we solve for y
-15x + -35y = -10
+----------------------
-29y = -58
-29 -29
y = 2
Now what we do is we choose and equation and solve for x, since it is still unknown. Any equation is fine but I will choose the second one since it has easy numbers.
3x + 7y = 2
3x + 7(2) = 2
3x + 14 = 2
-14 -14
----------------------
3x = -12
3 3
x = -4
Therefore our final answer is (-4,2)
I got a different answer..
and i don't see it as one of your choices, also your question is confusing since you're repeating it .-.
But anyways i got
9 students earned an 85 or higher.
2 earned 85
1 earned 86
3 earned 91
1 earned 94
2 earned 95.
2+1+3+1+2=9
The equations above are all in the format

, where

= the gradient, or slope.
So, in the first question,

, the gradient would be 4, because 4 is

in this equation (the number before the

).
The gradient of a line perpendicular to this line is equal to the negative reciprocal of the gradient of the line. A better way to explain it is if

= the gradient of the line and <u />

= the gradient of the perpendicular line then:

So in the first question, the gradient of the perpendicular line is

.