I think the answer is D because you have to move the decimal three times anyway, then you only need to add seven more zeroes to make it correct (in my opinion).
Answer:
The 95% confidence interval for the true proportion of bottlenose dolphin signature whistles that are type a whistles is (0.4687, 0.6123).
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
.
For this problem, we have 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:

The 95% confidence interval for the true proportion of bottlenose dolphin signature whistles that are type a whistles is (0.4687, 0.6123).
A = ((6 + 7 + 6) . 8)/2
A = 19 . 4
A = 76
The answer would be B.
Unit rate is something per time unit or other unit.
Hope this helps!
The answer to this would be 5x+6>=21. Just wanted points :P