Please help ASAP!
A clinical trial is performed to test a new drug designed to lower blood sodium levels. One hundred fifty participants are randomly assigned to take the new drug, and 150 participants are randomly assigned to take a placebo. After 6 months of treatment, blood sodium levels are measured and compared to the starting levels. For those who took the new drug, the blood sodium levels had a mean reduction of 27 points with a standard deviation of 5.2, while for those who took the placebo, the blood sodium levels showed a mean reduction of 22 points with a standard deviation of 3.9. Assuming the standard deviations are true for the entire population, calculate 90% confidence intervals and evaluate whether there is evidence the new drug is working.
A: The interval for the new drug is from 26.168 to 27.832 points. The interval for the placebo is from 21.376 to 22.624 points. Since the interval for the new drug lies above the interval for the placebo, there is evidence that the drug is working.
B: The interval for the new drug is from 26.302 to 27.698 points. The interval for the placebo is from 21.476 to 22.524 points. Since the interval for the new drug lies above the interval for the placebo, there is evidence that the drug is not working.
C: The interval for the new drug is from 26.302 to 27.698 points. The interval for the placebo is from 21.476 to 22.524 points. Since the interval for the new drug lies above the interval for the placebo, there is evidence that the drug is working.
D: The interval for the new drug is from 26.168 to 27.832 points. The interval for the placebo is from 21.376 to 22.624 points. Since the interval for the new drug lies above the interval for the placebo, there is evidence that the drug is not working.