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$\sum_{i=1}^{300} {1/3}$

My probability text wrote the above. I don't know how to interpret it since "i" doesn't show up in the indexed variable. How is this interpreted? Do I just add up 300 1/3's?

$\sum_{i=1}^{300} {n}$

Does this mean 300n?

delusionist
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    That's correct. – Wojowu Feb 11 '23 at 22:46
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    Yes, that's how it would be interpreted. But there's also a high chance that it is a typo, and that someone left off an $i$ that was supposed to be there. – JonathanZ Feb 11 '23 at 22:52
  • Also, given that it's showing up while studying probability, I'd make a small bet that it was $(1/3)^i$, but we'd have to see more of the problem to say that definitely. – JonathanZ Feb 11 '23 at 23:32

1 Answers1

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The rule for summations in this case is actually the same as in any other case. In general, the notation $$\sum_{i=1}^{300} E$$ means means to write the expression $E$ three hundred times, then replace $i$ with $1$ in the first expression, with $2$ in the second expression, and so on, and then add up the 300 results.

If the expression $E$ happens not to contain $i$, then there's nothing to replace, and you get $300$ unchanged expressions, which you add up to get $300E$.

MJD
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