[填空题]
At the end of a working day, a surveyfsoo( +k 1+8:;:vom ;ocyr woakii;br was conduclwu8t *cg,iv pm5y) 5vted at a company head office asking employees how frequently they tgpv,y 5mc t5vliw *)u8ake sick leave days per year.
The data is shown in the following table.
1. State whether the data is discrete or continuous.
The mean number of sick leave days per year is 4 .
2. Find the value of k .
In this survey, these employees were arranged in alphabetical order and every 5th person was asked for the number of sick leaves per year.
3. Identify the sampling technique used in the survey.
