On an architect's drawing of a house, 1 inch represents 7 feet. If the bedroom window is 5 inches long on the drawing, how long
1 answer:
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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.
a.
b.
The metal obey this law for values of strain until 0.05, where we have a linear relationship (each increase of 0.01 in the strain causes an increase of 100 in the stress). After this point, we don't have a linear relationship anymore.
c. Since an increase of 0.01 in the strain causes an increase of 100 in the stress, the slope is:
Now, calculating the coefficient b (y-intercept), we have:
So the equation is:
d.
The maximum value of stress is 560, and occurs at strain = 0.07.
