More Maths/Science help

Greebo

Greebo

Greebo

Caporegime
Joined
20 Jan 2005
Posts
45,777
Location
Co Durham
Okay, I need some help on the following. I am comparing three different lab results, two from one lab and one from another. Unfortunately they have reported their findings in different ways.

First lab:

10 to the power of 6.4 and 10 to the power of 6.7

The 2nd lab shows their results as 7.6 log 10.

Now I see it as follows:

10 to the power of 6.4 = 2,511,886
10 to the power of 6.7 = 5,011,872

However I am not a scientist so does 7.6 log 10 mean 10 to the power of 7.6?

If so that will be 39,810,717?
 
Last edited:
log (assuming you mean log to the base 10) means "what power of 10 gives:"

So log(10) is 1, because 10^1 = 10.

Does this help?
 
Greebo said:
Okay, I need some help on the following. I am comparing three different lab results, two from one lab and one from another. Unfortunately they have reported their findings in different ways.

First lab:

10 to the power of 6.4 and 1 to the power of 6.7

The 2nd lab shows their results as 7.6 log 10.

Now I see it as follows:

10 to the power of 6.4 = 2,511,886
10 to the power of 6.7 = 5,011,872

However I am not a scientist so does 7.6 log 10 mean 10 to the power of 7.6?

If so that will be 39,810,717?
Click to expand...

log10 7.6= .88081

10^ .88081= 7.6
 
Last edited:
Hmmmm. That is what I thought. log10 7.6 is indeed 0.88081.

However, that does not mean that 7.6 log10 is though?

It's the way they have reported their results which confuse me and it may just be a scientific thing.

to me log10 7.6 would be meaningless as why not report it as 0.88081. The other problem is this is counting the number of active proteins in a sample. 0.88081 does not seem a good answer especially when the expected result is to be in the miilions:confused:

To me what they are trying say is that the count number is the number which when having log 10 applied gives 7.6?

so as per y = log10(x) then 7.6 = log10(x)

Does that makes sense? Has anybody come across that way of reporting it?
 
Last edited:
Well the way I'd normally interpret "7.6 log 10" is 7.6 * natural log of 10, that is log to the base e of 10^7.6.
 
Greebo said:
Hmmmm. That is what I thought. log10 7.6 is indeed 0.88081.

However, that does not mean that 7.6 log10 is though?

It's the way they have reported their results which confuse me and it may just be a scientific thing.

to me log10 7.6 would be meaningless as why not report it as 0.88081. The other problem is this is counting the number of active proteins in a sample. 0.88081 does not seem a good answer especially when the expected result is to be in the miilions:confused:

To me what they are trying say is that the count number is the number which when having log 10 applied gives 7.6?

so as per y = log10(x) then 7.6 = log10(x)

Does that makes sense? Has anybody come across that way of reporting it?
Click to expand...
oh

7.6 log 10 is log 10^7.6, so if its a power then it gets moved to the front of the log giving you 7.6 log 10
 
Greebo said:
So the answer is 39,810,717 then?
Click to expand...

I don't think so. If you assume log= log to the base ten, then 7.6log10 is just 7.6. If log= log to the base e, 7.6log(10) is about 17.6. The only other thing i can think of is if they got confused between log and 10^ , but i can't really tell.
 
Last edited:
lord filbuster said:
I don't think so. If you assume log= log to the base ten, then 7.6log10 is just 7.6. If log= log to the base e, 7.6log(10) is about 17.6.
Click to expand...

As much as my maths brain screams you are right, I think it's just a science way of posting the results badly. Afterall, when your expected answer is millions then 17.6 doesn't make any sense either. :confused:
 
Greebo said:
As much as my maths brain screams you are right, I think it's just a science way of posting the results badly. Afterall, when your expected answer is millions then 17.6 doesn't make any sense either. :confused:
Click to expand...

Are they measuring in the same units, though? I mean I think you try to imply they are but it's worth checking.
 
Greebo said:
As much as my maths brain screams you are right, I think it's just a science way of posting the results badly. Afterall, when your expected answer is millions then 17.6 doesn't make any sense either. :confused:
Click to expand...

A "science way of reporting the results badly"? :confused:

It sounds like what you're reading is context-dependent, and you don't seem to get the context sufficiently well to explain to us what you're after.

Post the entire lab report, and we can deduce the meaning for you.


For the record, "7.6 log 10", as written, should be interpreted as "7.6 * natural_log of ten", which is ~17.5. If the "10" is a subscript, then it implies the log is taken to base 10, and you're missing a number (the thing that the logarithm is applied to).

Anyway, since the order of magnitude between the two quantities you are comparing is so different I suspect you're trying to equate apples with oranges. After all, no-one would use a logarithmic representation for a number in the millions. Post the entire report so we can see what you're actually asking.
 
Last edited:
Scientists aren't always good mathematicians ;)

I will go and cut and paste the relevant section. The 10 is subscript and I should have made that clear. There is no other numbers after the 10 and this "7.6 log 10" is referred to many times in the report.

As for apples and oranges, both reports from both labs were testing for the same thing. Expected results are in the millions. The higher, the better the result.

If it's any help, the 2nd lab is French!
 
Last edited:
Greebo said:
Scientists aren't always good mathematicians ;)

I will go and cut and paste the relevant section. The 10 is subscript and I should have made that clear. There is no other numbers after the 10 and this "7.6 log 10" is referred to many times in the report.

As for apples and oranges, both reports from both labs were testing for the same thing. Expected results are in the millions. The higher, the better the result.

If it's any help, the 2nd lab is French!
Click to expand...

if the 10 is a subscript, they have effectively written 7.6log()
It's completely meaningless.
 
Here you go boys:

Suspension for injection containing inactivated Bluetongue Virus serotype 8 antigen, at least 7.1 (log10)* per 1-ml dose, to stimulate active and specific immunity against Bluetongue Virus serotype 8 in cattle and sheep.*CCID50 Equivalent to titre prior to inactivation
Click to expand...

CCID50 = Cell Culture Infectous Dose to kill 50% of the cells

both 10 and 50 in subscript.

Sorry, I forgot the log10 was in brackets if that makes any difference?
 
Greebo said:
Scientists aren't always good mathematicians ;)

I will go and cut and paste the relevant section. The 10 is subscript and I should have made that clear. There is no other numbers after the 10 and this "7.6 log 10" is referred to many times in the report.
Click to expand...

This isn't mathematics, it's just data representation. No scientist or engineer publishing a formal report would be without these very basic (i.e. year-9 level) skills.

As lord filbuster says, 7.6 log_10 () ,by itself, is a meaningless representation. I'm sure we'll see what the report is saying, but if it's in French I will be of no help! :)
 
Greebo said:
Here you go boys:



CCID50 = Cell Culture Infectous Dose to kill 50% of the cells

both 10 and 50 in subscript.

Sorry, I forgot the log10 was in brackets if that makes any difference?
Click to expand...

ah, i think they have perhaps given all values in logarithms for some reason. It looks like they mean the value is 7.1 after you have taken the log of it. It looks like they actually mean 10^7.1.
 
Last edited:
lord filbuster said:
ah, i think they have perhaps given all values in logarithms for some reason. It looks like they mean the value is 7.1 after you have taken the log of it. It looks like they actually mean 10^7.1.
Click to expand...

Yeah, that seems to be what they're saying; the value is 7.6 on a log_10 scale. It's admittedly an odd way of writing it, but I imagine they're referring some plots based on a log-10 scale somewhere.

So to answer your original question, they seem to be reporting the answer as 10^7.6. Which seems closer to what you were expecting. And yes the way they've written it seems to be non-standard and confusing. So I apologise for my earlier condescending tone :p The full sentence was needed to see the answer though.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom