Hi Hamed,
To count the number of times RH>75.3%, first you store your dataset in a variable and take a counter (initialize to 0) variable in a for loop. Then check for the condition whether RH>75.3%, if so then set count=count+1. The final count value will give the required frequency. For example, consider the below code:
Count=0;
for i=1:length(data)
if(data(i)>75.3)
Count=Count+1;
else
end
end
