Answer:
a) 0.6032
b)
Lower limit: 0.48
Upper limit: 0.72
Step-by-step explanation:
In a sample with a number n of people surveyed with a probability of a success of
, and a confidence level of
, we have the following confidence interval of proportions.

In which
z is the zscore that has a pvalue of
.
Question a:
In a random sample of 63 professional actors, it was found that 38 were extroverts.
We use this to find the sample proportion, which is the point estimate for p. So

Question b:
Sample of 63 means that 
95% confidence level
So
, z is the value of Z that has a pvalue of
, so
.
The lower limit of this interval is:

The upper limit of this interval is:

Rounding to two decimal places:
Lower limit: 0.48
Upper limit: 0.72
Start with

Subtract
from both sides:

Divide both sides by 

And thus we solved the expression for l:

Answer:
B. Linear decreasing
Step-by-step explanation:
500%
1. Subtract old value from new value
2. Divide the difference from old value
3. Multiply quotient by 100 to make it a percentage