1. A researcher is conducting a study to determine the mean trough dosage of medication for a population. Assuming a previous study was conducted for the same medication and the mean trough dose was...

1. A researcher is conducting a study to determine the mean trough dosage of medication for a population. Assuming a previous study was conducted for the same medication and the mean trough dose was found to be 490 mg with a standard deviation of 40 mg, calculate the margin of error for a 95% confidence interval assuming the previous study enrolled 350 individuals.
A) E = ± 4.19
B) E = ± 3.52
C) E = ± 0.22
D) E = ± 78.40