A calculator manufacturing company checks 500 calculator units and finds that 25 of them have non-functioning keys. What is the relative frequency of a non-defective calculator from this batch of items?
Relative frequency of non-defective calculators = (Total number of non-defective calculators) / (Total number of calculators)
Relative frequency of non-defective calculators = (500 - 25) / 500 = 475 / 500 = 0.95
Therefore, the relative frequency of a non-defective calculator from this batch of items is 0.95 or 95%.