Additionally these might work. Suppose you have data:

dataorig = RandomInteger[{-10, 10}, 1000];

You can then generate a list of values vs repetitions like so:

data = SortBy[Tally[dataorig], First];

Of course, you can always reconstruct something with the same distribution as the original:

datarestore = Flatten[ConstantArray[#[[1]], #[[2]]] & /@ data];

The way described in the first answer is more elegant:

datarestore = Table[#[[1]], {#[[2]]}] & /@ data

Note that you can get a histogram directly from the data by using a BarChart:

BarChart[data[[All, 2]], ChartLabels -> data[[All, 1]]]

From the restored data it is easy to compute the mean and the standard deviation:

N@Mean[datarestore]

and

N@StandardDeviation[datarestore]

You can also use WeightedData to achieve something that you can easily evaluate:

dataweight=WeightedData @@ Transpose[data]

and then

N@Mean[dataweight]

and

N@StandardDeviation[dataweight]

Interestingly:

N@StandardDeviation[dataweight] == N@StandardDeviation[datarestore]

is False.

Cheers,

Marco