To determine the average water use, 109 people must be sampled.
1.9 gallons is the standard deviation.
E = 0.15 gallons maximum error
1.9 gallons on average
90% is the critical value.
1.645 is the 90% confidence interval.
sample size requirement,
n = (((z ÷ 2) × σ) ÷ E)²
n = (((1.645 ÷ 2) × 1.9) ÷ 0.15)²
n = ((0.8225 × 1.9) ÷ 0.15)²
n = (1.5627 ÷ 0.15)²
n = (10.418)²
n = 108.53 ≈ 109
As a result, the minimal sample size necessary to determine the mean water use = 109.
It is determined by dividing the average standard error by the squared of the sample size, and it decreases with increasing sample size. In other words, when the sample size is sufficiently big, the population mean approaches the population mean.
To learn more about the sample interval at
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Answer:
dz / dt = -50
Step-by-step explanation:
To solve the chain rule must apply, we have all the necessary values to make the calculation, as follows:
using the chain rule, we find:
dz / dt = (∂z / ∂x) * (∂x / ∂t) + (∂z / ∂y) * (∂y / ∂t)
Evaluating when t = 9, we have to:
fx (6, 4) * g '(9) + fy (6, 4) * h '(9)
We know that g '(9) = −6; h '(9) = 4; fx (6, 4) = 9; fy (6, 4) = 1
Replacing:
(9 * -6) + (1 * 4) = -50
Por lo tanto dz / dt = -50
Can’t see the pic .........................
Do 3 minus 1.9
- To make this easier I would do
3 - 2 = 1
1 + 0.1 = 1.1
The simplest and probably the best way to understand this problem is to make up a problem that obeys what you have been given. It doesn't have to be realistic. It just has to obey the conditions. Let us suppose that you thought the diameter of the tire is 1 yard. That would mean the circumfrence is pi * d
C = 3.14 * 1
That would mean that the circumference is 3.14 yards. It would also mean that you would have to have the wheel turn 1760 yards / /3.14 yards / revolution which is about 561 revolutions / mile. So the way I have set up the problem, my equation is d = 561 * R where R is the number of revolutions.
Now let's see what happens when you say "O my Goodness, the wheel diameter is really 32 inches" which 0.8888888 yards what happens now?
Now you still have to go 1760 yards How many revolutions is that?
C = pi * d
C = 3.14 * 0.88888888
C = 2.79111 yards
How many revolutions does it take to 1760 yards.
R = 1760 // 2.78111 yards / revolution
R = 631 revolutions / mile. What happened?
Your constant goes up if the wheel diameter goes down. Think about this. Do you ride a bicycle? I do. It makes perfect sense to me that if the wheel is small, it will have to turn more often to go a mile. No matter where that 0.00125 comes from or how it was derived, the constant will have to go up if the wheel gets smaller.
