Geometric analysis
Estimates are produced for the number of babies born worldwide each year. The estimates for 2004 and 2008, given in thousands of births to the nearest thousand, were 130,350 and 137,804 respectively. Assume that successive yearly estimates are in a geometric progression.
The anual increase in births between 2004 & 2008 is 1.43%
Find the estimates for 2006 and 2011 (to the nearest thousand)
when estimating 2011 is it
(100+(1.43*7))%x130,350 = 143398.035
the answer given is 144000
surely the answer is wrong seeing as to the nearest thousand its 143000?
The anual increase in births between 2004 & 2008 is 1.43%
Find the estimates for 2006 and 2011 (to the nearest thousand)
when estimating 2011 is it
(100+(1.43*7))%x130,350 = 143398.035
the answer given is 144000
surely the answer is wrong seeing as to the nearest thousand its 143000?
(edited 10 years ago)
Scroll to see replies
Original post by 50ShadesOfRay
Estimates are produced for the number of babies born worldwide each year. The estimates for 2004 and 2008, given in thousands of births to the nearest thousand, were 130,350 and 137,804 respectively. Assume that successive yearly estimates are in a geometric progression.
The anual increase in births between 2004 & 2008 is 1.43%
Find the estimates for 2006 and 2011 (to the nearest thousand)
when estimating 2011 is it
(100+(1.43*7))%x130,350 = 143398.035
the answer given is 144000
surely the answer is wrong seeing as to the nearest thousand its 143000?
The anual increase in births between 2004 & 2008 is 1.43%
Find the estimates for 2006 and 2011 (to the nearest thousand)
when estimating 2011 is it
(100+(1.43*7))%x130,350 = 143398.035
the answer given is 144000
surely the answer is wrong seeing as to the nearest thousand its 143000?
Everything in red is incorrect
The answer is 143673 so is 144000 to the nearest thousand
Original post by TenOfThem
Everything in red is incorrect
The answer is 143673 so is 144000 to the nearest thousand
The answer is 143673 so is 144000 to the nearest thousand
The 1.43% is definitely correct.
Original post by 50ShadesOfRay
The 1.43% is definitely correct.
No it isn't
130350 x 1.0143^4 is not 137804
Original post by TenOfThem
No it isn't
130350 x 1.0143^4 is not 137804
130350 x 1.0143^4 is not 137804
no the annual increase is 1.43%
the increase over four years is 5.72%
Original post by 50ShadesOfRay
no the annual increase is 1.43%
the increase over four years is 5.72%
the increase over four years is 5.72%
Perhaps you could explain where you get that value from?
The 4th root of 1.05718 is not 1.0143
Oh, I see - you divided by 4 - that is not correct
(edited 10 years ago)
Original post by TenOfThem
Perhaps you could explain where you get that value from?
The 4th root of 1.05718 is not 1.0143
Oh, I see - you divided by 4 - that is not correct
The 4th root of 1.05718 is not 1.0143
Oh, I see - you divided by 4 - that is not correct
MPM1(21)sigma.pdf
here is an attachment to the homework, it is q11, and the answers are listed below q12
Original post by 50ShadesOfRay
MPM1(21)sigma.pdf
here is an attachment to the homework, it is q11, and the answers are listed below q12
here is an attachment to the homework, it is q11, and the answers are listed below q12
I understood the question and I know what the answers are as I have worked them out
It is you who are not doing the correct calculations
Original post by TenOfThem
I understood the question and I know what the answers are as I have worked them out
It is you who are not doing the correct calculations
It is you who are not doing the correct calculations
so they've given me the wrong answers?
Original post by 50ShadesOfRay
so they've given me the wrong answers?
no the answers given are fine
Original post by TenOfThem
no the answers given are fine
the answer given is 1.4%... I am right?
Original post by 50ShadesOfRay
the answer given is 1.4%... I am right?
The answer is 1.4% to 1dp, yes
Your answer of 1.43% is incorrect
Original post by TenOfThem
The answer is 1.4% to 1dp, yes
Your answer of 1.43% is incorrect
Your answer of 1.43% is incorrect
i obviously don't know what i'm doing then, forget it, thanks anyway
Original post by 50ShadesOfRay
i obviously don't know what i'm doing then,
Indeed
Did you read post 6 where I told you exactly what your error was?
Original post by TenOfThem
Indeed
Did you read post 6 where I told you exactly what your error was?
Did you read post 6 where I told you exactly what your error was?
why is dividing by 4 incorrect though, it's from 2004 to 2008 that's 4 years?
Original post by 50ShadesOfRay
why is dividing by 4 incorrect though, it's from 2004 to 2008 that's 4 years?
Because a geometric progression involves powers of the ratio, not multiples of the ratio
So you need the 4th root, not divide by 4
Original post by TenOfThem
Because a geometric progression involves powers of the ratio, not multiples of the ratio
So you need the 4th root, not divide by 4
So you need the 4th root, not divide by 4
are you saying the fourth root of 5.72%?
Original post by 50ShadesOfRay
are you saying the fourth root of 5.72%?
No
The 4th root of 1.05718
Do you understand how geometric progressions work
I assume that you did he 2008 value divided by the 2004 value and you had 1.05718
So that means
2004 x ? x ? x ? x ? = 2008
so ?^4 = 1.05718
Original post by TenOfThem
No
The 4th root of 1.05718
Do you understand how geometric progressions work
I assume that you did he 2008 value divided by the 2004 value and you had 1.05718
So that means
2004 x ? x ? x ? x ? = 2008
so ?^4 = 1.05718
The 4th root of 1.05718
Do you understand how geometric progressions work
I assume that you did he 2008 value divided by the 2004 value and you had 1.05718
So that means
2004 x ? x ? x ? x ? = 2008
so ?^4 = 1.05718
is it 1.3999% ?
Original post by 50ShadesOfRay
is it 1.3999% ?
Yes
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