I have a question can someone tell me what the check s1^2/s2^2 mean? S= standard deviation. The BOLD lettering and numbers.

The main trial is conducted and involves a total of 200 patients.Patients are enrolled and randomized to receive either the experimental medication or the placebo.The data shown below are data collected at the end of the study after 6 weeks on the assigned treatment.

Experimental (n=100)

Placebo (n=100)

Mean (Std Dev) Systolic Blood Pressure

120.2 (15.4)

131.4 (18.9)

% Hypertensive

14%

22%

% With Side Effects

6%

8%

1. Generate a 95% confidence interval for the difference in mean systolic blood pressures between groups.

Check s₁²/s₂²= 15.4²/18.9²=0.66