standard error

Neither are relevant for Paper F5 - they are not in the syllabus. They are to do with sampling theory and used to be in the syllabus for Paper F2, but were removed many, many years ago.

thank you sir but in f5 article risk and uncertainity i read

Although the article was written by a member of the F5 examining team, it was primarily for students studying for Paper P4 (even though some of it is certainly relevant for F5). Standard deviation and standard error are not in the syllabus for Paper F5 and cannot be examined. What is covered in our free lectures is what is in the syllabus and what you need for the exam.