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I have a question on scientific notation in a calculated CI and how to present it. The value of my CI is: 1.623497e+01. So when I write that out do I say that the CI for that variable is 1.62... or is it 16.23 since the e+ means move the decimal one spot to the left?

kjetil b halvorsen
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  • This isn't really an "R" or Stack Overflow question. Also, whether you write the CI in scientific notation or not is either subjective or defined by the publication you're publishing in, but you'd never write 1.62 without the "e+01" in this example, because then it would be unclear. – Hack-R May 01 '20 at 02:23
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    I don't know what you mean by 'value of a CI' and I don't know how this bit of scientific notation arose, but in R, code `a = 1.623497e+01; a` yields 16.23497. I can't imagine a context where it would be wrong to write 14.23497 (or maybe round it to 14.235) if that number makes sense. – BruceET May 01 '20 at 06:05

2 Answers2

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xe+01 in R is the same as $x 10^1 = 10x$, so yes, the value you're mentioning is 16.23... The number of decimals you want to specify depends on the context.

milanmlft
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You definitely wouldn’t just give 1.6, since that’s the wrong number (and not just wrong because you rounded).

When I’ve presented values in scientific notation that software gives me with “e”, I’ve written out the scientific notation like I do in this example.

$$6.022\times10^{23}$$

(That’s approximately one mole from chemistry.)

I’m shocked, though, that R didn’t just write out 16.23. It doesn’t even save space to write the scientific notation; it’s longer! Consequently, it would be a bit silly to use scientific notation when you write your value.

Dave
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    `R`, as well as much other software, considers context when converting numbers for printing. You shouldn't be shocked to see values given in scientific notation: that merely reflects a context in which there is such a large range of absolute values in the output that scientific notation is needed to maintain reasonable precision. – whuber May 01 '20 at 17:30