A previous report from the Centers for Disease Control and Prevention (CDC) indicates that smokers, on average, miss 6.16 days of work per year due to sickness (including smoking-related acute and chronic conditions). Nonsmokers miss an average of 3.86 days of work per year. If two years later the CDC believes that the average days of work missed by smokers has not changed, it could confirm this by sampling. Consider the following sample:

Determine the sampling error of this sample, assuming that the CDC supposition is correct.