The replicate results (mg/L) obtained from calcium determination of a blood sample using atomic absorption spectrophotometry (AAS) and a new colorimetric method were as following: AAS : 11.2, 11.2, 10.6, 11.2, 9.7 and 10.0 Colorimetric : 9.2, 10.5, 9.7, 11.5, 11.6, 9.3, 10.1 and 11.2 Determine whether the mean of both methods have a significant difference at 95% confidence level