diff --git a/src/main/java/com/gdschongik/gdsc/domain/study/application/MentorStudyDetailService.java b/src/main/java/com/gdschongik/gdsc/domain/study/application/MentorStudyDetailService.java
index 0f22c7472..bba23ef6a 100644
--- a/src/main/java/com/gdschongik/gdsc/domain/study/application/MentorStudyDetailService.java
+++ b/src/main/java/com/gdschongik/gdsc/domain/study/application/MentorStudyDetailService.java
@@ -156,7 +156,7 @@ private List<StudyWeekStatisticsResponse> calculateStudyWeekStatistics(
         return studyDetails.stream()
                 .map((studyDetail -> {
                     boolean isCanceledWeek = !studyDetail.getCurriculum().isOpen();
-                    boolean isCanceledAssignment = !studyDetail.getAssignment().isOpen() | isCanceledWeek;
+                    boolean isCanceledAssignment = !studyDetail.getAssignment().isOpen() || isCanceledWeek;
 
                     if (totalStudentCount == 0) {
                         return StudyWeekStatisticsResponse.of(