Perhatikan tabel berikut! Nilai 0/25 ragam (varians) dari data yang disajikan adalah ... *

<p>Jawaban : 42,33</p><p>&nbsp;</p><p>▪️ Mean/rata-rata dari data kelompok<br>x̄ = ∑fixi/∑fi<br>dimana<br>fi : frekuensi kelas i<br>xi : nilai tengah kelas i</p><p>▪️ xi = (batas atas + batas bawah)/2</p><p>▪️ Varians(Ragam) data kelompok<br>S² = ∑ fi(xi - x̄)²/ ∑ fi</p><p>&nbsp;</p><p>Buat tabel statistik dari data sebagai berikut.</p><p>&nbsp;</p><p>Nilai..................fi........xi.....fixi.....<br>__________________________<br>21 - 25...............2.......23.....46<br>26 - 30...............8.......28.....224<br>31 - 35...............9.......33.....297<br>36 - 40...............6.......38.....228<br>41 - 45...............3.......43.....129</p><p>46 - 50...............2.......48.....96<br>__________________________<br>jumlah ............30...............1.020</p><p>&nbsp;</p><p>x̄ = ∑fixi/∑fi<br>= 1.020/30<br>= 34</p><p>&nbsp;</p><p>Kemudian untuk mencari variansi, akan lebih mudah dibuat tabel hitung sebagai berikut. (angka dibulatkan sampai 2 desimal)</p><p>&nbsp;</p><p>Nilai..................fi........xi.........x̄..........(xi - x̄)²......fi(xi - x̄)²<br>_______________________________________________<br>21 - 25...............2.......23.......34........121...........242<br>26 - 30...............8.......28.......34..........36...........288<br>31 - 35...............9.......33.......34............1...........9<br>36 - 40...............6.......38.......34..........16...........96<br>41 - 45...............3.......43.......34..........81...........243</p><p>46 - 50...............2.......48.......34........196...........392<br>________________________________________________<br>jumlah ............30...............1.020.......................1.270</p><p>&nbsp;</p><p>S² = ∑ fi(xi - x̄)²/ ∑ fi<br>= 1.270/30</p><p>= 42,3333</p><p>≈ 42,33</p><p>&nbsp;</p><p>Jadi, varians nya adalah 42,33,</p>