Maths SL P2 can you lose points for using a GDC?

[daiisycurtis]

Hi,

So I'm been doing loads of past papers in maths and I was wondering: can points be taken off for using the GDC?

For example, as I have a TI-84+, I can do the invnorm, normalcdf etc for non-standardised means and standard deviations without calculating the standardised value z.

However, when I look at markschemes, they seem to suggest that you need to have worked out the z value... But I still get the correct result and show all of my working so surely it should be fine?

If anyone has any insight I'd be grateful as I'm not going to see my teacher for a while.

Daisy 

[kw0573]

Do you have a specific question in mind? Sometimes doesn't work directly if one of the parameters is unknown (eg find standard deviation or find mean). But invnorm is basically the table for you to look up so there's no way you can get out of it. 

[daiisycurtis]

So here for example in this question, part b. ii.

Here's the question and the mark scheme, and then what I did:

I didn't do exactly what the mark scheme says, so to speak, but I did enough and got the same result.  It's the same in quite a few of the different instances.

 

I know for most of the other TIs, you have to go through z, but I don't need to so surely doing it anyway would just be wasting my time?

thanks!

[kw0573]

Ok so if the mark for the step is in parentheses "(M1)" or "(A1)" then that means if you get the right answer, you will also get these marks even if they are not written. If you are unsure about about your answer than you can write the intermediates to get some part marks.

[daiisycurtis]

Ok perfect! Thanks so much for explaining this!