How compare todays sum(bytes_out) with average of other days in a month?

[Basavaraj]

reference:

| bucket _time span=1d
| stats sum(bytes*) as bytes* by user _time src_ip
| eventstats max(_time) as maxtime avg(bytes_out) as avg_bytes_out stdev(bytes_out) as stdev_bytes_out 
| eventstats count as num_data_samples avg(eval(if(_time < relative_time(maxtime, "@h"),bytes_out,null))) as per_source_avg_bytes_out stdev(eval(if(_time < relative_time(maxtime, "@h"),bytes_out,null))) as per_source_stdev_bytes_out by src_ip  
| where num_data_samples >=4 AND bytes_out > avg_bytes_out + 3 * stdev_bytes_out AND bytes_out > per_source_avg_bytes_out + 3 * per_source_stdev_bytes_out AND _time >= relative_time(maxtime, "@h")
| eval num_standard_deviations_away_from_org_average = round(abs(bytes_out - avg_bytes_out) / stdev_bytes_out,2), num_standard_deviations_away_from_per_source_average = round(abs(bytes_out - per_source_avg_bytes_out) / per_source_stdev_bytes_out,2)
| fields - maxtime per_source* avg* stdev*