Answer: 0.8%
Explanation:
Given : In a batch of 960 calculators, 8 were found to be defective.
i.e. Total calculators =960
Number of defective calculator = 8
We know that the probability of any event is given by :-

In percent,
![0.00833333333333*100=0.833333333333\%\\\\\approx0.8\%\ \ \ [\text{Rounding to the nearest tenth.}]](https://img.qammunity.org/2018/formulas/mathematics/college/7uox5qxxs3059owovf5twebzd22v77p223.png)
Hence, the probability that a calculator chosen at random will be defective=0.8%