Answer:
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
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 = 1.28.
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 7.6 - 0.1 = 7.5
The upper end of the interval is the sample mean added to M. So it is 7.6 + 0.1 = 7.7
The 80% confidence interval for the mean number of toys purchased each year is between 7.5 and 7.7 toys.
Answer: 
Step-by-step explanation:
I hope you mean y = x² - 12 and not y = 2x - 12.
You switch the y and x variables:
x = y² - 12
And solve for y:
x + 12 = y²

what is the domain of the function: {(1, 3); (3, 5); (5, 7); (7, 9)}? a. {1, 3, 5, 7, 9} b. {1, 3, 5, 7} c. {1, 9} d. {3, 5, 7,
Papessa [141]
B. 1, 3, 5, and 7 are x values. Domain is the x value.
Answer:
A square has 4 sides of equal length, so if you have been given the length, this is also the breadth.
Therefore, the perimeter is 4 x side length.
For example, imagine a square with side length 3 cm. As all four side lengths are equal, the perimeter would be 4 x 3 cm = 12 cm