Example 16. The quality check of the produced parts showed that on average, the defect rate is $7.5 \%$. Find the most probable number of standard parts in a batch of 39 pieces, randomly selected.

翻译结果如上，保留了原文的换行和格式。
Solution. Extracting a standard part (event $A$) and extracting a non-standard part (event $\bar{A}$) are opposite events. From the condition, it follows that $q=0.075$, so $p=1-0.075=0.925$. Since in this case $n=39$, the formula (3.1.5) for determining the most probable number of occurrences of event $A$ takes the form

$$
39 \cdot 0.925 - 0.075 \leq k_{0} \leq 39 \cdot 0.925 + 0.925
$$

from which $36 \leq k_{0} \leq 37$. The most probable number of standard parts is 36 or 37.