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:
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Answer:
6:21
Step-by-step explanation:
because there is 6 roses and 21 other types 6/21 = 6:21
Triangle area is 1/2 bh
So 11.9 is about 12, 7.1 is about 7.
7x12 = about 84 sq, cm