Men with localized prostate cancer (median age=67) were randomly assigned to either radical prostatectomy (removal) or observation. During the follow-up time (median time=10years), 30 of 360 assigned to observation had died from prostate cancer, and 19 of the 362 assigned to surgery had died from prostate cancer. Complete parts (a) through (d) below.

I need help to calculate the chi-square test statistic