Answer:
b. =8.5+1.96*3/SQRT(45), and =8.5-1.96*3/SQRT(45)
Step-by-step explanation:
Sample size (n) = 45
Sample mean (M) = 8.5 minutes
Variance (V) = 9 minutes
Z-score for a 95% confidence interval (z) = 1.96
A confidence interval is defined by the following expression:
Applying the given data:
Writing in Excel statements, the limits of the interval would be
=8.5+1.96*3/SQRT(45), and =8.5-1.96*3/SQRT(45)
Therefore, the answer is alternative b.
