Frankly, the way you've stored your data is rubbish and making your work much harder.
Firstly, Your ranges shouldn't be stored as char arrays. It should be a 2 x numranges matrix or table.
Secondly, since the rows of Range have absolutely nothing to do with the rows of entryTime, they shouldn't be stored together in the same table. That would avoid pointless storing nans in entryTime if there are more ranges or god knows what as a filler in Ranges if there are more entryTimes.
So let's fix this:
ranges = regexp(data.Range, '([^-]+)-(.+)', 'tokens', 'once'); %plenty of other ways to split the data
ranges = array2table(str2double(vertcat(ranges{:})), 'VariableNames', {'lowerbound', 'upperbound'})
entryTimes = data(:, 'entryTime');
entryTimes(isnan(entryTimes.entryTime), :) = []
Then your problem is trivial:
rangecount = rowfun(@(l, u) sum(entryTimes.entryTime >= l & entryTimes.entryTime <= u), ranges, 'OutputVariableNames', {'count'})
