Student or Learner
Should I write incorrect or wrong?
Since I needed to input a lot of data, I sometimes make mistakes.
The mistakes like input Peter as Pete.
There were too many data, so I input some incorrect / wrong data into the system.
Was it the original data that was wrong, or were you provided with the correct data but you entered it incorrectly? It's not possible to tell from your sentence alone. I assume from the background you give that you are saying that sometimes you type the information in incorrectly. However, if the reader does not have that background information and only reads your sentence, it won't be clear whether the error lies with the data or with you.
Note to other (BrE) natives - am I the only person whose gut reaction was that it should be "There was too much data"? (Note: I am aware that data is the plural!)
a bit confusing
according to a dictionary
Definition of data noun from Cambridge Dictionary Online: Free English Dictionary and Thesaurus
there is an example:
The data was/were collected by various researchers.
in this example, data can be treated as a singulat noun, so "was" can be used.
Collins Thesaurus of the English Language – Complete and Unabridged 2nd Edition. 2002 © HarperCollins Publishers 1995, 2002Usage: From a historical point of view only, the word data is a plural. In fact, in many cases it is not clear from context if it is being used as a singular or plural, so there is no issue: when next needed the data can be accessed very quickly. When it is necessary to specify, the preferred usage nowadays in general language is to treat it as singular, as in: this data is useful to the government in the planning of housing services. There are rather more examples in the Bank of English of these data than this data, with a marked preference for the plural in academic and scientific writing. As regards data is versus data are, the preference for the plural form overall is even more marked in that kind of writing. When speaking, however, it is best to opt for treating the word as singular, except in precise scientific contexts. The singular form datum is comparatively rare in the sense of a single item of data.