MedVision ad

reaĺly really quick question :D (2 Viewers)

DepressedPenguino

Active Member
Joined
Mar 27, 2014
Messages
363
Gender
Male
HSC
2015
Q: how many years will it take for the population of kangaroos to double?

Say i worked out that it takes approximately 18.0196 years for a population of kangaroos to double, do i express my answer as 18 years or 19 years?
 

InteGrand

Well-Known Member
Joined
Dec 11, 2014
Messages
6,109
Gender
Male
HSC
N/A
(Out of curiosity) What would we have done if the calculated value had come out as 18.0000000001?
 

Squar3root

realest nigga
Joined
Jun 10, 2012
Messages
4,927
Location
ya mum gay
Gender
Male
HSC
2025
Uni Grad
2024
(Out of curiosity) What would we have done if the calculated value had come out as 18.0000000001?
imo, we would not be able to get to that many sig, fig. accuracy so I would round my answer down to 18 but in general I learnt that you just round up because when you round down, you may not meet the constraint of the question but when you round it up, you do.

I don't think you'll lose too many marks for rounding down if your process and working is correct, just depends on the marker
 

VBN2470

Well-Known Member
Joined
Mar 13, 2012
Messages
440
Location
Sydney
Gender
Male
HSC
2013
Uni Grad
2017
Lol, then you would probably just leave it at 18 then, can't be too fussy about it.
 

Speed6

Retired '16
Joined
Jul 31, 2014
Messages
2,949
Gender
Male
HSC
N/A
But the real question is, what if kangaroos didn't exist?

We must go deeper....
 

BLIT2014

The pessimistic optimist.
Moderator
Joined
Jul 11, 2012
Messages
11,591
Location
l'appel du vide
Gender
Undisclosed
HSC
2014
Uni Grad
2018
I'd put rounded to 19 years.
 
Last edited:

PhysicsMaths

Active Member
Joined
Dec 9, 2014
Messages
179
Gender
Male
HSC
2015
In this case, the kangaroo is 7 days away from being born. So the question is... do you get no kangaroo at all, or a prematurely born kangaroo?
 

braintic

Well-Known Member
Joined
Jan 20, 2011
Messages
2,137
Gender
Undisclosed
HSC
N/A
Why would you turn 18.02 into 19. It's not asking for an integer number of years .... the kind of question people are getting confused with would say something like "What is the minimum number of complete years for the population to double?". And if you did do this, why on earth would anyone call it 'rounding' ?

And .... why does anyone believe that the exponential growth model could possibly be used for a population of only 17 bacteria? The model is based on the fact that individual randomness is averaged out over large populations, and its use is completely meaningless in such small populations.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 2)

Top