What is the value of f(x) = –x^2 – 2 when x = –1?
2 answers:
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Answer:
Step-by-step explanation:
- A circle's equation consist on the following expression:
, where r is the magnitude of the radio, and (a,b) are the coordenates of the center of the circle.
- In this case, a=2 and b= - 3, because the circle is centered in (x,y)=(2, - 3).
- The radio, which is the distance between the center of the radio to any point in its border, equals r=2 (because of the scale of the graphic, in this case two squares of the grid equal 2 units, then r=2).
- Finally, using the previous information to replace in the equation
, where the fact that r=2 and
was used.
Answer:
The 95% confidence interval for the mean amount of the increase is ($541.6, $588.4). This means that we are 95% sure that the mean amount of increase of all customers who charge at least $3,000 in a year is between these two values.
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 Z-table as such z has a p-value of .
That is z with a pvalue of , so Z = 1.96.
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.
The lower end of the interval is the sample mean subtracted by M. So it is 565 - 23.4 = $541.6
The upper end of the interval is the sample mean added to M. So it is 565 + 23.4 = $588.4
The 95% confidence interval for the mean amount of the increase is ($541.6, $588.4). This means that we are 95% sure that the mean amount of increase of all customers who charge at least $3,000 in a year is between these two values.