Answer: The last 3 choices
Answer:
(x - 3)² + (y - 5)² = 16
Step-by-step explanation:
the equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k ) are the coordinates of the centre and r the radius
given (h, k ) = (3, 5 ) we require to find r
r is the distance from the centre to a point on the circle
given x = - 1 is a tangent the r is the distance between the x- coordinates
r = | 3 - (- 1) | = | 3 + 1 | = | 4 | = 4
then equation of circle is
(x - 3)² + (y - 5)² = 4² , that is
(x - 3)² + (y - 5)² = 16
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.