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There is a relationship between confidence interval and standard deviation:

Where

is the mean,

is standard deviation, and n is number of data points.
Every confidence interval has associated z value. This can be found online.
We need to find the standard deviation first:

When we do all the calculations we find that:

Now we can find confidence intervals:

We can see that as confidence interval increases so does the error margin. Z values accociated with each confidence intreval also get bigger as confidence interval increases.
Here is the link to the spreadsheet with standard deviation calculation:
https://docs.google.com/spreadsheets/d/1pnsJIrM_lmQKAGRJvduiHzjg9mYvLgpsCqCoGYvR5Us/edit?usp=sharing
Answer
<em>length = width + 15</em>
<em>Area = length * width; area is 54 square feet.</em>
<em>Two equations are:</em>
<em>L = W + 15</em>
<em>L * W = 54</em>
<em>To solve, we substitute first equation into second equation:</em>
<em>(W + 15) * W = 54</em>
<em>w^2 + 15w = 54</em>
<em>w^2 + 15w - 54 = 0</em>
<em>(w+18)(w-3) = 0</em>
<em>w = -18 or 3</em>
<em>The width cannot be negative, so 3 is the width and since length is 15 more than width, length is 18:</em>
<em />
<em>Length = 18 feet</em>
<em>Width = 3 feet</em>
<em />
<em />
Answer:
x = 11.2
Step-by-step explanation:
hypotenuse = 8.4 (radius) + 5.6 = 14
using the Pythagorean theorem:
x² = 14² - 8.4² = 196 - 70.56 =125.44
x = √125.44 = 11.2
Answer:
D.
Step-by-step explanation:
-2/5 - (-9/15) = -2/5 + 9/15.
both of those equations are equivalent.
hope this helps.