Update order_statistics.md (#1729)

docs/src/order_statistics.md

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 # Order Statistics
 
-The $i$th [Order Statistic](https://en.wikipedia.org/wiki/Order_statistic) of a random sample of size $n$ from a univeriate distribution is the $i$th element after sorting in increasing order.
+The $i$th [Order Statistic](https://en.wikipedia.org/wiki/Order_statistic) of a random sample of size $n$ from a univariate distribution is the $i$th element after sorting in increasing order.
 As a special case, the first and $n$th order statistics are the minimum and maximum of the sample, while for odd $n$, the $\lceil \frac{n}{2} \rceil$th entry is the sample median.
 
 Given any univariate distribution and the sample size $n$, we can construct the distribution of its $i$th order statistic: