Let n = required random sample size.
Assume that the population standard deviation is known as σ.
Let m = sample mean.
At the 95% confidence level, the expected range is
(m - k(σ/√n), m + k(σ/√n))
where k = 1.96.
Therefore the error margin is 1.96(σ/√n).
Because the error margin is specified as 3% or 0.03, therefore
(1.96σ)/√n = 0.03
√n = (1.96σ)/0.03
n = 128.05σ²
This means that the sample size is about 128 times the population variance.
Answer:
Smallest sample size = 128.05σ², where σ = population standard deviation.
Answer:
The solution of the linear equation is: (6,7)
Step-by-step explanation:
This being that:
x + y = 13
1/2x + y = 10
What you do in order to find the solution is either (2 ways):
- Substitution
- Elimination
I'm sure that either way, you'll get the same thing. I used: Substitution.
To do this choose either if you want to find [x] or [y] first, then substitute it in. I will choose to find [x] first.
<h2>x + y = 13</h2><h2><u> - y </u> </h2><h2>x = 13 - y</h2>
Now substitute it into:
1/2x + y = 10
1/2(13 - y) + y = 10
1/2(13 -y) + y= 10
<h2>Then to get rid of fraction, instead of dividing, you multiply with reciprocal</h2><h2>1/2 · 2/1 (They cancel out) Leaving you with:</h2><h3 /><h3>(13 - y) 2(y) = 2(10)</h3><h3>(Everything is multiplied, except for 13 - y, because it had parenthesis to protect it.)</h3><h3>13 - y + 2y = 20</h3><h3 /><h2>13 + y = 20</h2><h2><u>- 13 - 13</u></h2><h2> <u>y = 7</u></h2><h2 /><h2>You now have your [y] for your coordinate.</h2><h2>(x, 7), now time to find your [x]</h2><h2 />
Now you substitute your [y] into your equation:
1/2x + (7) = 10
<h2>
1/2x + 7 = 10</h2><h2><u>
-7 = -7</u></h2><h2>
1/2x = 3</h2><h2>
(To get rid of fraction, multiply on both sides with reciprocal)</h2><h2>
1/2 cancels out with 2/1</h2><h2>
x = 2(3)</h2><h2>
x = 6</h2><h2>You now have your [x] coordinate.</h2><h2 /><h2>This is your coordinate: </h2><h2>(6,7)</h2><h2>
</h2>
Answer:
12 gallons 2 quarts
Step-by-step explanation:
4 + 1 = 5
1/5 = 0.2
0.2 = 20%