awk '
        {
                if ( $1 in L )
                {
                        L[$1] = L[$1] > $2 ? $2 : L[$1]
                        H[$1] = H[$1] < $2 ? $2 : H[$1]
                }
                else
                {
                        L[$1] = $2
                        H[$1] = $2
                }
                S[$1] += $3
                N[$1]++
        }
        END {
                for ( k in L )
                {
                        SL += L[k]
                        SH += H[k]
                }
                for ( k in L )
                        print k, H[k] - L[k], SH - SL, S[k] / N[k]
        }
' file