Answer:
"A Type I error in the context of this problem is to conclude that the true mean wind speed at the site is higher than 15 mph when it actually is not higher than 15 mph."
Step-by-step explanation:
A Type I error happens when a true null hypothesis is rejected.
In this case, as the claim that want to be tested is that the average wind speed is significantly higher than 15 mph, the null hypothesis has to state the opposite: the average wind speed is equal or less than 15 mph.
Then, with this null hypothesis, the Type I error implies a rejection of the hypothesis that the average wind speed is equal or less than 15 mph. This is equivalent to say that there is evidence that the average speed is significantly higher than 15 mph.
"A Type I error in the context of this problem is to conclude that the true mean wind speed at the site is higher than 15 mph when it actually is not higher than 15 mph."
Answer:
yes
Step-by-step explanation:
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.
