Answer:
a) The confidence interval is .
Step-by-step explanation:
We have to calculate a confidence interval (CI) of a difference of proportions.
For the existing procedure, the proportion is:
For the new procedure, the proportion is:
To calculate the CI, we need to estimate the standard deviation
For a 90% CI, the z-value is 1.64.
Then, the CI is:
Option B: The area of the trapezoid is 157.5 m²
Explanation:
We need to determine the area of the trapezoid.
The area of the trapezoid can be determined by the formula,
where h is the height, a and b are the base of the trapezoid.
From the figure, it is obvious that ,
and
Substituting these values in the formula, we have,
Simplifying the terms, we have,
Multiplying the terms in the numerator, we have,
Dividing, we get,
Thus, the area of the trapezoid is 157.5 m²
Hence, Option B is the correct answer.
Let
If M is the midpoint, the x and y coordinates of M are the average of the x and y coordinates of P and Q:
We can solve this expression for the coordinates of Q:
Plug in the values for the coordinates of M and P to get