Experimental unit

Part 1 of this question asks what is the experimental unit.

The question states:

to test the effect of small proportions of coal in sand for manufacturing concrete, several batches were mixed under particularly identical conditions except for the variation in the percentage of coal. From each batch, several cylinders were made and tested for breaking strength.

The answer says the experimental unit is cylinder.

I suggest the experimental unit is batch, in that this is the unit to which the experimenter has applied the treatment.

The definition of experimental unit I am using comes from "Applied Linear Statistical Models" 5th ed by Kutner, Nachtsheim, Neter and Li, p652, and it notes

An experimental unit is the smallest unit of experimental material to which a treatment can be assigned; the experimental unit is thus determined by the method of randonmisation.

In this case, the batches would have had the proportion of coal randomly assigned to them, not the cylinders.

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"The smallest division of the experimental material to which we apply the treatments and on which we make observations on the variable under study, is termed as experimental unit". In this example the smallest unit is cylinder on which we make observation.