Police are investigating the attack.
Calls For Review Of Maths Exam
Opposition parties have called for a review into why this year's new Higher maths exam sat by pupils in Scotland was "more demanding than intended".
The pass mark was lowered to less than 34% after the country's exams body admitted it was too hard.
The Scottish Qualifications Authority (SQA) said the marking process for the new Higher had taken the level of difficulty into account but there are fears some pupils could still have been disadvantaged.
Almost 143,000 students are receiving their exam results today after sitting the new Highers for the first year and National 4 and 5 qualifications for the second year.
The new qualifications were brought in as part of the Curriculum for Excellence reforms.
Pupils were also able to sit exams in existing Access, Intermediates and Highers which were "dual-run" for 2015 alongside the new qualifications.
Many students had complained that the new maths exam was more difficult than they had expected.
A total of 10,854 pupils sat the existing Higher maths while 10,220 sat the new Higher maths.
The attainment rates were 73.1% and 70.8% respectively, similar to that of previous years, but the pass mark for the new exam was lowered to 33.8%, compared with 43% for the existing exam.
Dr Janet Brown, SQA's chief executive and Scotland's chief examining officer, said: "As in every year, we carry out a review of assessments to ensure candidates have been able to display their skills, knowledge and understanding.
"If required, grade boundaries are adjusted to take account of any assessments that were easier or more demanding than intended to ensure all candidates received the grades they deserved."
Labour's education spokesman Iain Gray called for a review to prevent the same issues being repeated next year.
"The pupils who raised concerns about the difficulty of the new Higher maths exam have been vindicated. It's true that pass marks are adjusted each year but it's extraordinary to see this drop to just 33.8%," he said.
"Pupils sitting the Higher maths exam next year shouldn't have to go through what young people did last May."
Scottish Liberal Democrat education spokesman Liam McArthur said: "Cutting the pass mark for Higher maths may help those students who persevered but it will do nothing for pupils who left exams early on being presented with an exam paper including topics not covered in the coursework.
"Ministers must undertake a full investigation into why this happened."
Scottish Conservatives young people spokeswoman Liz Smith said: "People would understand if modest modifications had been made to pass rates to reflect realistic changes in exams.
"But this reduction is drastic, and shows just how badly the SQA got it wrong."
SQA figures show that there were a record 156,000 Higher passes this year, up 5.5% on 2014.
Overall, a total of 107,295 pupils sat the new Highers, with a pass rate of 79.2%. A further 92,555 pupils sat the existing Highers, recording a pass rate of 76.7%, slightly down on the 2014 pass rate of 77.1%.
The pass rate for the National 4 was 93.3%, with 114,173 passes, while pupils achieved 229,870 passes at National 5 level, resulting in a success rate of 79.8%.
Advanced Higher passes increased by 4% to a record level of 18,899, with pass rate of 80.9%.
Education Secretary Angela Constance said: "This is another strong performance by Scotland's young people.
"They have worked hard and I congratulate each and every one of them, as well as the families and carers and teachers and lecturers who have provided support."
Speaking during a visit to Craigmount High School, in Edinburgh, she added: "The SQA for every exam every year have well-established processes that ensure that standards are maintained and that no young person is disadvantaged.
"There are safeguards in place to ensure young people get the results that they rightly deserve.
"The SQA have already said that the new Higher maths exam was indeed unusually hard, but we should be reassured that there are well-established processes that have checks and balances that test the performance of any exam in any year in any subject, to ensure that it is both fair as well as robust."
Pupils at Craigmount High School took an exam compiled under the old higher model but Ms Constance insists they and others like them were not given an unfair advantage.
"Young people will not be disadvantaged by the Higher that they sat, whether it is the existing or the new one," she said.
Another girl was airlifted to hospital.
The attack happened on Waverley Bridge.
Opposition parties are criticising the figures.
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