Set Analysis calculation

[NickBentley]

I am using the 2 expressions in a straight table below to calculate sales data for when the temperature is either above 30 or between 25 -30. 

=sum({<[Store Max Temp]={">=30"}>}Sales_Value)

=sum({<[Store Max Temp]={">=25<30"}>}Sales_Value)

These are working fine when only 1 store is selected. 

However, when multiple stores are selected sales numbers appear in both columns when really I would like just the average temperature of the stores combined to be the  [Store Max Temp]  calculated. 

Is there a way of calculating the average before the set analysis take effect? 

Thanks in Advance! 

[sergio0592]

In your chart, try with :

=avg(sum({<[Store Max Temp]={">=30"}>+<[Store Max Temp]={">=25<30"}>    }Sales_Value))

[NickBentley]

Thanks for your reply sergio0592. 

Unfortunately it is not returning the solution I am after. 

Need to find away of averaging the store temperatures before the set analysis is appraised.