The following table reflects the delay, in minutes, experienced by the low cost "lowcost airlines" last year
Delay | Number of flights
0-10 | 160
10-20 | 240
20-40 | 280
40- 60 | 120
(a) What is the average delay per flight?
(b) Calculate the minimum delay that a flight may experience to be within 42% of the flights with the greatest delay.
(c) Let us suppose that in the "Travel airline", the average flight delay was 15 minutes with a typical deviation of 12 minutes. In which of the two airlines is the delay more homogeneous? Reason the answer
I have doubts since the intervals are given every 10 minutes and every 20. I add the number of flights from 0-20 It is correct to do that?? I will not be losing data from the observations? to group it to 400 and I get the following table
Class | ni | Ci | Ci*ni | Ni
0-20 | 400 | 10 | 4000 | 400
20-40 | 280 | 30 | 8400 | 680
40-60 | 120 | 50 | 6000 | 800
800 18400
The average is 18400/800= 23 minute
b) Asks for the 58th percentile, so
P20 = 20+ ((0,58*800)-400)*20 /280 = 24,57 minute
c)I calculate the typical deviation of the data I have from the variance
class | ni-(Ci^2)
0-20 | 40000
20-40 | 252000
40-60 | 300000
592000
S^2 = (592000/800) -(23^2) = 211
To calculate the typical deviation I calculate the square root of the variance and it gives me 14,52 minute.
If I compare with the line of 15 minutes of average delay and 12 of typical deviation, it has a better pint than having 23 minutes on average and 14.52 of deviation. Is that the reasoning?