I have two data sets of hourly measurements from two different time periods. During each time period, the values drop below a given threshold for different amounts of time.
I would like to develop a statistical basis for determining if the amount of time spent below the threshold during period 1 is significantly different from the amount of time spent below the threshold during period 2.
For example, if the temperature drops below 10 deg C for 15 hours during one week and for 22 hours during another week, the difference in the number of hours below 10 deg C would be 7.
Are there any statistical methods to determine if this difference of 7 hours is a "significant" amount of time? (among the 168 hours that are in a week)