Blockchains are used to store and transmit digital and secure information. This is made possible by creating a chain of chronologically and cryptographically linked data blocks. An oracle is often used to feed the blockchain to ensure the data inserted are reliable. The nature of data sent to the oracle can vary a lot from one application to another. In the scope of the Internet of Things, data provided by sensors may be corrupted when the sensor is damaged or has been corrupted. In this case, it is important for the oracle to include an efficient tool able to detect these outliers. The Grubbs test is such an efficient tool. This article aims at presenting the impact of the use of the Grubbs test on the performance of the oracle. It shows that not only it allows to significantly increase the quality of the data inserted in the blockchain by identifying outliers, it also keeps the algorithmic complexity of the oracle as low as possible.