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:

Answer:
what exactly is the question to the problem ? it looks like it's already solved ? are you suppose to find something or ?
Answer:

Step-by-step explanation:
To find the value of an exterior angle of a regular polygon, we can apply a formula.



I would say its A but I'm not 100%