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:
140
Step-by-step explanation:
17.89, is this an option?
Jabardasth question is the scale factor is 2
<span>4.8 (x+4)=2.6
Use distributive property
4.8x + 19.2= 2.6
Subtract 19.2 from both sides
4.8x = -16.6
Divide 4.8 on both sides so that the only thing remaining on the left side is the variable x.
Final Answer: x = -3.458</span>