4. (8 points) In a physical fitness test for sixth-grade students at Yingchun Primary School, 900 students met the standards, and those who participated in the test but did not meet the standards accounted for $25 \%$ of the students who participated in the test. Those who did not participate in the physical fitness test due to certain reasons accounted for $4 \%$ of the total number of students in the grade. The number of students who did not participate in the physical fitness test is $\qquad$ people.
【Answer】Solution: $900 \div(1-25 \%) \div(1-4 \%) \times 4 \%$
$$
\begin{array}{l}
=1200 \div 96 \% \times 4 \% \\
=1250 \times 4 \% \\
=50 \text { (people) }
\end{array}
$$

Answer: The number of people who did not participate in the physical fitness test is 50.
Therefore, the answer is: 50.