2013 HSC exam Q28(b)(iv) CONTRADICTS THE SYLLABUS!!!!!! (1 Viewer)

[tywebb]

The 2013 General Mathematics 2 HSC Paper in Question 28 (b)(iv) asks students to calculate the height of 17 year old male using the equation calculated in the previous part of the question.

The sample answers published by the board of studies is as follows:
Sample answer:
h = 6a + 80
when a = 17
h = 6 × 17 + 80
= 182
∴ 182 cm
(OR from extrapolating graph.)


The syllabus states:
"It should be noted that the predictions made using a line of best fit:
– are more accurate when the correlation is stronger and there are many data points
– should not be used to make predictions beyond the bounds of the data points to which it was fitted
– should not be used to make predictions about a population that is different from the population from which the sample was drawn." (BOSTES, 2012, p.109).

Shouldn't the correct answer have been for the student to state that a line of best fit should not be used to make predications outside the bounds of the data?

... or am I missing something?

 

[cutemouse]

– should not be used to make predictions beyond the bounds of the data points to which it was fitted

That's a bit contradictory in itself ... usually when one refers to a "prediction", they are referring to something outside the data points to which the data was fitted. Anything inside would be the "fitted value" of the model ...