uncertainty because the good experiment result linearity should be equal one. Therefore, linearity is be 0.9997 then be an accept value of the result For the result of experiment, the amount of FBC sample tablet is 63.21 mg (In fact, FBC is contained Fe 200 mg), and the amount of Haemo-vit sample tablet is 33.36 mg n fact, Haemo-vit is contained Fe 135 mg). Therefore, the amount of Fe that detected is less than real. There are several processes; grind sample, wet digestion, dilution, for preparing the sample, so it may affect the value of amount of Fe is lost. In the same way, the company may label over the real it is possible. Moreover, these fail value may come from the using of the same container for detecting the value from spectrophotometer. These reasons are shown that the percentage relative error of FBC sample is 68.40 percent, and Haemo-vit sample is 75.29 percent, so both of these results are low accuracy should be higher than 5%ERROR. As well as the value of percent relative standard deviation of both sample shown about 1.17 percent of FBC sample and 20.04 percent of Haemo-vit sample. When interpret this value percent relative standard deviation, the data shown about FBC sample has high precision and Haemo-vit sample has low precision by took this data compare with theory of percent relative standard deviation. The range of percent relative standard deviation is, if the value have lower or equal 5 percent therefore this data is high precision. onto