Add second year

second/semester2/CT248/Assignments/Assignment-08/six.m

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+clear;
+
+% 1. read in the file and confirm the number of records (336,766)
+flights = readtable("Flights.csv"); 
+numRecords = height(flights)
+
+% 2. convert "origin" & "dest" to strings (from cell type) 
+flights.origin = string(flights.origin); 
+flights.dest = string(flights.dest); 
+
+
+% 3. check the number of missing values for the departure time 
+numMissing = sum(ismissing(flights.dep_delay))
+
+% 4. filter all the missing values from the departure delay and check the
+% difference in the number of records
+flights_clean = flights(~isnan(flights.dep_delay), :);
+numRecordsClean = height(flights_clean);
+disp("Number of records in flights = " + numRecords); 
+disp("Number of records in flights_clean = " + numRecordsClean);
+
+% 5. confirm the difference in records between the two tables 
+diff = numRecords - numRecordsClean
+
+% 6. Remove any departure delay greater than 2 hours (120 minutes). This 
+% leaves 318,798 observations. 
+flights_final = flights_clean(flights_clean.dep_delay <= 120, :); 
+height(flights_final)
+
+% 7. Generate the following table and graph, showing the average delay per 
+% month. 
+months = unique(flights_final.Month);
+
+res1 = table(months, zeros(size(months)), 'VariableNames', {'Month', 'AvgDelayMonth'});
+for i = months(1):length(months)
+    month_delays = flights_final.dep_delay(flights_final.Month == i);
+    avg_delay_month = mean(month_delays); 
+    res1.AvgDelayMonth(i) = avg_delay_month;
+end
+res1
+plot(res1.Month, res1.AvgDelayMonth, '-o');
+title('Average Delay by Month');
+
+% 8. Generate the following table and graph, showing the average delay per
+% hour.
+hours = transpose(1:24);
+
+res2 = table(hours, zeros(size(hours)), 'VariableNames', {'Hour', 'AvgDelayHour'});
+for i = hours(1):length(hours)
+    hour_delays = flights_final.dep_delay(flights_final.hour == i);
+    avg_delay_hour = mean(hour_delays); 
+    res2.AvgDelayHour(i) = avg_delay_hour;
+end
+res2 = res2(~isnan(res2.AvgDelayHour),:);
+res2
+plot(res2.Hour, res2.AvgDelayHour, '-o');
+title('Average Delay by Hour of the Day');
+
+% 9. Generate the following table and graph, showing the average delay by
+% month and by origin 
+res3 = renamevars(removevars(groupsummary(flights_final,["Month","origin"],"mean","dep_delay"),'GroupCount'), 'mean_dep_delay', 'AvrDelayMonthOrigin')
+
+jfk = res3(res3.origin == 'JFK', {'Month', 'AvrDelayMonthOrigin'});
+subplot(3,1,1);
+plot(jfk.Month, jfk.AvrDelayMonthOrigin, '-o');
+title("JFK");
+
+ewr = res3(res3.origin == 'EWR', {'Month', 'AvrDelayMonthOrigin'});
+subplot(3,1,2);
+plot(ewr.Month, ewr.AvrDelayMonthOrigin, '-o');
+title("EWR");
+
+lga = res3(res3.origin == 'LGA', {'Month', 'AvrDelayMonthOrigin'});
+subplot(3,1,3);
+plot(lga.Month, lga.AvrDelayMonthOrigin, '-o');
+title("LGA");