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.
10 thanks and i'll answer this
Step-by-step explanation:
Answer:
y=9cm
x=90°
Step-by-step explanation:
y=9cm(being perpendicular)
x=90°=being perpendicular)
Answer:
-39991'
Step-by-step explanation:
We require the sum of 7 terms of the G.S. -1, 6, -36 .....
The common ratio r = 6/-1 = -6 and the first term = -1.
Sum of n terms = a1 . (r^n - 1) / (r - 1)
Sum of 7 terms = -1 * (-6)^7 - 1) / (-6 - 1)
= -1 * 39991
= -39991 (answer).
<h3>
Answer: Choice E</h3>
======================================================
Explanation:
Think of 25 as 25/1 and 5 as 5/1
Choice E is really saying 
which becomes 
. Note the second fraction flips and we change to a multiplication sign.
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Or you could think of it like this:
to help see why the answer is E.
