Answer:
A sample of 179 is needed.
Step-by-step explanation:
We have that to find our 
level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of 
.
That is z with a pvalue of 
, so Z = 1.44.
Now, find the margin of error M as such
In which 
is the standard deviation of the population and n is the size of the sample.
A previous study found that for an average family the variance is 1.69 gallon?
This means that 
If they are using a 85% level of confidence, how large of a sample is required to estimate the mean usage of water?
A sample of n is needed, and n is found for M = 0.14. So
Rounding up
A sample of 179 is needed.
Answer:
Subtract c from each side, using the subtraction property of equality
Step-by-step explanation:
0 = ax^2 + bx + c
Subtract c from each side, using the subtraction property of equality
-c = ax^2 + bx + c-c
-c = ax^2 + bx
Make use of the fact that side lengths in similar triangles are proportional.
.. 30/18 = (20 +x)/20
.. 20*(30/18) -20 = x . . . . multiply by 20, subtract 20
.. 33 1/3 -20 = x . . . . . . . . evaluate the product
.. 13 1/3 = x
1. x = -4 ; f(x) = -(-4) = 4
2. x = -3 ; f(x) = 2(-3) + 1 = -5
3. x = 0 ; f(x) = 2(0) + 1 = 1
4. x = 2 ; f(x) = 2 + 3 = 5
5. x = 5 ; f(x) = 5 + 3 = 8
Answer:
what you arest mine but the other one says no answer what
Step-by-step explanation:
