Average Line across the Bar Chart

Hi,

I have designed to show average of data for whole range of years, but when selected particular bars in chart average seems to be not dynamic. As, it is shown for whole data not for specific seleced part.

Please suggest how to make this average line to be dynamic(based on selection in the visual itself).

Hi v-huizhn-msft

Using DAX, I found that I am needing help on the same matter. Here is one of the lines on the char

SchedLagMedian = MEDIAN('Locations'[Important_Column])

Here is another line. 

Month/Year = FORMAT(DATE(LEFT('Locations'[Months], 4), RIGHT('Locations'[Months], 2), 1), "MMM-YY")

lastly, here is the horizontle line like what I am trying to replicate dynamically

LagTarget = 14

Essentially I need a horizontle line like that above but referenced from another chart.  That code is here: 

Summarized Lag Table = 
UNION((ADDCOLUMNS(SUMMARIZE('Locations',Locations[Areas],"Value", 14,"Target", BLANK()
    ),"Type", "Goal", "Sort", 1 )),
CALCULATETABLE(ADDCOLUMNS(SUMMARIZE('Locations',Locations[Areas]), 
        "Value", CALCULATE(MEDIAN('Something'[Important_Column])),
        "Target", BLANK(),
        "Type", "Performance",
        "Sort", 2 ),
    'Something'[Time] = 1 ),
ADDCOLUMNS(SUMMARIZE(Locations, Locations[Areas]),
        "Value", SUMMARIZE('Lag Medians', "Average", AVERAGE('Lag Medians'[Value])),
        "Target", BLANK(),
        "Type", "All Locations",
        "Sort", 3))

This produces a line graph that has a flat horizontle line and a performance line.  Another line needs to exist which is the calculated median of performance.  Perhaps something like this... 

Median = MEDIAN(SUMMARIZE('Locations'[Important_Column])) 

But when I put that in, I simply get the same as if I added the median at each month rather than the average median.  Please help? Thanks in advance!

Mark