A second maths-related exam cock-up has been revealed this afternoon, following an error in an NCEA test yesterday.

A "discrepancy" in a question on the Level 2 calculus paper sat by year 12 students yesterday morning has been confirmed to the Herald by the New Zealand Qualifications Authority (NZQA) this evening.

It comes after the exam body admitted this morning there was an error in a table for a Level 3 statistics exam yesterday afternoon, and apologised for the mistake.

READ MORE: Exam botch-up: I lost all confidence


Around 15,000 students were expected to sit that exam, and stunned pupils said they were left stumped and freaking out by the error.

Now a teacher has described to the Herald a "glaring" mistake in yesterday's Level 2 maths exam, which approximately 20,000 students took part in.

Question 2B asked students: "The line y = ax + b is a tangent to the graph of the function y = 2x squared - 3x + 1 at the point (3,2). Find the values of a and b."

"The only problem is that point (3,2) doesn't lie on the graph," the teacher, who wished to remain anonymous, said.

"It's actually a point that's off the graph. What it meant to have said was point (2,3)."

A "disappointed" student had raised the error with him, he said.

Students were unable to "do anything with it and it puts them off for the next questions", he said.

"[As a student], you're not going to be going, 'I wonder if the examiner for the whole of New Zealand's made a mistake here'."

He questioned how NZQA could have made such a bungle.

"If you go to systems like iGCSEs and IBs, the exams are spotless," he said.

"I don't know how it's possible for that to get in there. It's not a mistake that's hidden, it's glaringly obvious."

NZQA confirmed the blunder this evening.

"It has been brought to our attention that yesterday's Level 2 Mathematics examination had a discrepancy related to a graph in one part of one question," the authority said in a statement.

"Markers are aware of this and will be able to discern whether it has had an impact on students and will adjust for it. "

Five complaints had been lodged so far in relation to error, NZQA said.

Earlier today, NZQA deputy chief executive Kristine Kilkelly apologised to students who sat the statistics exam, and said that no-one would be disadvantaged by the question.

However, students said the stress and worry over the mistake had affected their performance on other exam questions on the paper, and many had spent a disproportionate amount of time pondering the table.