Answer:
a) cluster sampling
Step-by-step explanation:
In cluster sampling method, each member of a population is assigned to one and only one group.This means clusters are formed through probability method usually a simple random sampling.The participants in the clusters are the only one to be surveyed.
In this example, simple random sampling is used to identify 12 home rooms(cluster) where a group of 20 students (participants) in each room is given the survey.
Answer:
- Josh's book lands first
- Ben's lands about 0.648 seconds later
Step-by-step explanation:
Using the given equation for v=60 and s=40, the height of Ben's book is ...
h(t) = -16t² +60t +40
We want to find t when h(t) = 0, so we're looking for the solution to ....
0 = -16t² +60t +40
Using the quadratic formula, we find the positive value of t to be ...
t = (-60 -√(60² -4(-16)(40)))/(2(-16)) = (15 +√385)/8 ≈ 4.3277
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Similarly, the height of Josh's book is ...
0 = -16t² +48t +40
t = (-48 -√(48² -4(-16)(40)))/(2(-16)) = (12 +√304)/8 ≈ 3.6794
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The time before Josh's book lands is shorter by ...
4.3277 -3.6794 ≈ 0.6482 . . . . . seconds
Josh's book reaches the ground first, by about 0.648 seconds.
Answer: Bottom left corner
Angle DEC and Angle DEH
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Explanation:
I recommend opening your favorite paint program, and using different colors to mark on the drawing as I have done below (see attached image). Note how angle DEC is in red and angle DEH is in blue. The two angles are adjacent, meaning they share the same ray (in this case, ray ED) and they form a straight angle.
Because they form a straight angle, or straight line, this means the two angles are supplementary. Supplementary angles always add to 180.
Order the number:
15,34,71,75,75,78,78,78,82,90,90,94,100
Mode:78
Mean≈74.8
Median:78 is your final answer. Hope it help!