Regression to the mean and selection bias are the superfluous variables that are removed by randomly choosing schools for the experiment and control groups.
A statistical phenomenon known as regression to the mean (RTM) states that if a random outcome of any measurement or event is severe in the first example, the second or following outcomes will be less extreme. In other words, it will be somewhat near to the distribution's mean or center.
According to regression to the mean (RTM), if an experiment's first result is extreme, the second result will be more in line with the population mean.
Decisions are made incorrectly as a result of this prejudice.
To mitigate the detrimental impacts of regression to the mean, organizations can exercise critical thinking and undertake a randomized controlled trial (RCT) with an experimental group and a control group.
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They are expected to win back on average 50 cents back, which is a bad investment.
Answers:
- Total equation: x+y = 80
- Legs equation: 2x+4y = 248
- How many ducks? 36
- How many cows? 44
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Further explanation:
- x = number of ducks
- y = number of cows
x+y = 80 is the total equation (ie the head count equation) since we assume each animal has 1 head, and there are 80 heads total.
That equation can be solved to y = 80-x after subtracting x from both sides.
The legs equation is 2x+4y = 248 because...
- 2x = number of legs from all the ducks only
- 4y = number of legs from all the cows only
- 2x+4y = total number of legs from both types of animals combined
We're told there are 248 legs overall, so that's how we ended up with 2x+4y = 248
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Let's plug y = 80-x into the second equation and solve for x.
2x+4y = 248
2x+4( y ) = 248
2x+4( 80-x ) = 248
2x+320-4x = 248
-2x+320 = 248
-2x = 248-320
-2x = -72
x = -72/(-2)
x = 36
There are 36 ducks
Now use this x value to find y
y = 80-x
y = 80-36
y = 44
There are 44 cows.
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Check:
36 ducks + 44 cows = 80 animals total
36*2 + 44*4 = 72 + 176 = 248 legs total
The answers are confirmed.
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