Answer:
Systematic sampling
Step-by-step explanation:
Systematic sampling is a sampling technique in which the first sample selection is a random selection but other subsequent selection of samples occurs within a fixed sampling interval. The determination of this interval is based on the division of the population size by sample size.
Let assume that, our first random selection is [tex]i^{th}[/tex] unit, then the other fixed selection occurs at a fixed sampling interval of k.
Therefore, using systematic sampling method, the sampling unit will be every [tex]k^{th}[/tex] unit after the [tex]i^{th}[/tex] unit.
From the question given:
We notice that the manager selects a sampling unit every 15th hour. This tells us that he is taking the sampling unit by the usage of a fixed time interval.
Hence, this appears to be a systematic sample.