Percentage increase

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Kayok

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A person stated that the school district had 25 cases of COVID during Aug-Oct and now in Nov has 39 cases. They claim that’s a 300% increase. How did they calculate that number?
 
Kayok said:
A person stated that the school district had 25 cases of COVID during Aug-Oct and now in Nov has 39 cases. They claim that’s a 300% increase. How did they calculate that number?
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Can you please state EXACTLY (verbatim) what was claimed?

As you wrote it - the increase is nowhere near 300%.
 
Kayok said:
A person stated that the school district had 25 cases of COVID during Aug-Oct and now in Nov has 39 cases. They claim that’s a 300% increase. How did they calculate that number?
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We need the entire statement and context.

One possibility I see is that they may mean that the rate of new cases per month increased by 300%, from 25/3 = 8.3 to 39, which is well over 300% increase. But the exact wording is essential. I'm assuming that the number 25 is a total over the three months, not an average of some sort.

One of my peeves this year has been the frequency with which I have to check whether data is about cumulative totals or daily new cases, or whatever. Too often data are not described carefully enough.
 
thanks so much. Your assumption was correct that the number 25 was a total to an increase of 39 which gives a 156% increase not 300%. My grandson is enrolled in statistics and said “Probably just a mistake. It’s statistics. Doesn’t matter”
 
Kayok said:
thanks so much. Your assumption was correct that the number 25 was a total to an increase of 39 which gives a 156% increase not 300%. My grandson is enrolled in statistics and said “Probably just a mistake. It’s statistics. Doesn’t matter”
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An increase from base value of 29 to 35 - would be ~56% increase.

If it stayed at 29 - there will be 0% increase.

(35-29)/29 ~ 0.56 \(\displaystyle \ \to \ \ \) 56 % increase
 
Kayok said:
thanks so much. Your assumption was correct that the number 25 was a total to an increase of 39 which gives a 156% increase not 300%. My grandson is enrolled in statistics and said “Probably just a mistake. It’s statistics. Doesn’t matter”
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Well, no. We really need to see the exact wording of the statement, because my guess did not imply a 156% of 56% increase.

What I said was that if the 25 was the total new cases over a three-month period, which you say it is, then that would be an average of 25/3 = 8 1/3 new cases per month. If there were then 39 cases in one month, that is an increase of 39 - 8 1/3 = 30 2/3 cases/month, and (30 2/3)/(8 1/3) = (92/3)/(25/3) = 92/25 = 3.68, or 368%. [I actually calculated it as 39/(25/3) - 1 = 3.68, which is easier.]

So they may actually be right, if what they say is that the rate increased by over 300%.

And statistics do matter. And so do wrong statistics, or miscommunication of statistics, whichever this is.
 
Subhotosh Khan said:
An increase from base value of 29 to 35 - would be ~56% increase.

If it stayed at 29 - there will be 0% increase.

(35-29)/29 ~ 0.56 \(\displaystyle \ \to \ \ \) 56 % increase
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Thanks. You got some digits transposed trying to explain that my stated solution was not correct but I understood the gist of it. The cases went from 25 to 39 which was a 56% increase, nowhere near 300%! So we all think there was a mistake in the description. Thanks all!
 
Kayok said:
Thanks. You got some digits transposed trying to explain that my stated solution was not correct but I understood the gist of it. The cases went from 25 to 39 which was a 56% increase, nowhere near 300%! So we all think there was a mistake in the description. Thanks all!
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You still don't seem to understand. My proposal is that they are correct, if what they said, or meant, was that the rate of new cases increased by over 300%, which is the appropriate quantity to measure; but you have not answered my request for a quote of the exact, complete, wording of the statement. Please do so.
 
Kayok said:
Thanks. You got some digits transposed trying to explain that my stated solution was not correct but I understood the gist of it. The cases went from 25 to 39 which was a 56% increase, nowhere near 300%! So we all think there was a mistake in the description. Thanks all!
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You said:

"You got some digits transposed"​

Could you please show where and which digits were transposed?
 
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