Blinding is part of this, as the participants do not know whether they received the competitor's product.
Im pretty sure it’s A,B,D
Answer:
Quinn did not make a mistake. This is because everything she did is correct and also if we calculate the expression without doing anything she did, we see that she has the right answer.
The correct answer is the first choice, ($1818.30, $5077.70.)
To find this, we first find the z-score based on the confidence level:
Convert 95% to a decimal: 95%=95/100 = 0.95
Subtract from 1: 1-0.95 = 0.05
Divide by 2: 0.05/2 = 0.025
Subtract from 1: 1-0.025 = 0.975
Using a z-table (http://www.z-table.com) we see that this value is associated with a z-score of 1.96.
Next, we identify

Next we find

Next we find

Next, we multiply this value by z:
1.96(831.479) = 1629.70
The confidence interval is given by