Penelitian ini bertujuan untuk mengembangkan tes melek statistik. Tes ini valid pada konten, valid pada konstruk, dan dapat diandalkan untuk mengukur dan menilai literasi statistik siswa. Literasi statistik dikembangkan melalui 3 tahap pengembangan: pendahuluan, perencanaan, dan pengembangan. Validitas isi literasi statistis dilakukan dengan penilaian ahli, validitas konstruk dianalisis dengan metode analisis faktor konfirmatori dua tingkat berdasarkan kriteria Goodness Of Fit serta reliabilitas model dianalisis menggunakan construct reliability. Hasil validitas konstruk menunjukkan bahwa setiap item dapat diukur secara signifikan oleh 6 aspek literasi statistis. Model konseptual literasi statistik berada dalam kategori good fit, dengan nilai RMSEA 0,023, CFI 0, 91 dan GFI 1, 00, ini berarti bahwa model literasi statistik good fit. Hasil uji reliabilitas model yang dilihat dari nilai construct validity, diperoleh nilai sebesar Literasi statistis ini diuji pada 150 siswa dari 3 sekolah SMA di Kota Medan. Hasil uji reliabilitas konstruk diperoleh nilai construct reliability (CR) setiap variable lates sebesar 0,83 ≥ 0,70 dan nilai Variance Extracted (VE) sebesar 0,61 ≥ 0,5. Berdasarkan nilai CR dan VE, maka konstruk literasi statistis siswa berada pada kategori reliabilitas konstruk yang baik.

Mathematical resilience is a student's ability to survive and be positive when facing difficulties and anxiety in learning mathematics as indicated by the ability to work collaboratively with groups, and have language skills to communicate mathematical understanding. Learning mathematics online caused various negative conditions for students; reduced learning interactions, internet disturbances, material that was not optimally explained, even low support for studying at home. This study aims to find out about students’ mathematical resilience when taking online mathematics lessons during the Covid 19 Pandemic. A qualitative phenomenological design was used, in which 20 high school students in Medan, participated. Data was collected through an open online questionnaire and interview, due to the implementation of social restrictions in Medan. Thematic analysis was used to interpret the data. The results are summed up: (1) Implementation and use of mathematics learning platforms during the Covid 19 Pandemic; (2) Adaptation of students learning mathematics; (3) Students' belief in learning mathematics; (4) students' communication skills during mathematics learning; (5) The Support for learning mathematics. This study recommends several suggestions to strengthen students' mathematical resilience in order to overcome mathematical difficulties and problem when taking online mathematics learning.

Students' Mathematical Resilience when learning mathematics online during the Covid 19 pandemic must be identified. The goal is to ensure online learning does not harm students' mathematics learning outcomes. Various studies on students' mathematical resilience in offline mathematics learning have identified that mathematical resilience affects students' mathematical performance. This study investigated the resilience of students perceived by students, as well as those observed by teachers during online mathematics learning during the covid 19 pandemic. Research data were obtained from 22 students who studied math online. Using an open questionnaire and interviews, the data were analyzed. It was revealed that students had difficulties in understanding math material and completing tasks given by the teacher. It was also revealed that teachers had difficulty assessing students' mathematics learning outcomes objectively and transparently. Students also find it difficult to get support in online mathematics learning from teachers and families. Students find it difficult to adapt, low interest and motivation during online mathematics learning, even the teacher's limitations in controlling students' online learning strategies.