8 3. Helen is studying one of the qualitative variables from the large data set for Heathrow from 2015. She started with the data from 3rd May and then took every 10th reading. There were only 3 different outcomes with the following frequencies Outcome A B C Frequency 16 2 1 (a) State the sampling technique Helen used. (1) (b) From your knowledge of the large data set (i) suggest which variable was being studied, (ii) state the name of outcome A. (2) George is also studying the same variable from the large data set for Heathrow from 2015. He started with the data from 5th May and then took every 10th reading and obtained the following Outcome A B C Frequency 16 1 1 Helen and George decided they should examine all of the data for this variable for Heathrow from 2015 and obtained the following Outcome A B C Frequency 155 26 3 (c) State what inference Helen and George could reliably make from their original samples about the outcomes of this variable at Heathrow, for the period covered by the large data set in 2015. (1) _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________ _____________________________________________________________________________________