T(ea) for Two Again Tests Between the Means of Related Groups Ratri Psikologi Pendidikan UNJ
Introduction to the t test for dependent samples The difference between the student’s scores on the pretest and on the post test is the focus Participants are being tested more than once There are two groups The appropriate test statistic is t test for dependent means
Ilustrasi Peneliti ingin mengetahui apakah metode pembelajaran yang diberikan pada siswa-siswanya memperlihatkan adanya perbedaan prestasi yang signifikan. Perlakuan I: siswa diberi pre-test Perlakuan II: siswa diberi perlakuan metode pembelajaran Perlakuan III; siswa diberi post-test Hasil skor pre-test dan post-test diuji perbedaan meansnya dengan metode t-test
The Path to Wisdom and Knowledge
Computing the Test Statistic Rumus: t = D nD2 – (D)2 n-1 D = sum of all the differences between groups n = jumlah pasangan yang diobservasi
Contoh perhitungan Pretest Postest Diffrerence D2 3 7 4 16 5 8 9 6 2 1 -1 ... N=25 Sum = 158 Sum = 188 Sum = 30 Sum = 180 Mean = 6.32 Means = 7.52 Means = 1.2 Means = 7.2
Step by Step... Step 1 Step 2 Step 3 Pernyataan hipotesis nul dan hipotesis penelitian H0 = µpostest = µpretest H1 = Xpostest = Xpretest Step 2 Setting the LoS (Type I error) LoS = 0.05 Step 3 Selection of the appropriate test statistic t-test for dependent means why??
Step by Step... Step 4 Compute! t = 30 (25x180) – 302 25 – 1 = 30 = 2.45 √150 Step 5 Determination of the value needed for rejection H0 df = n-1 = 25-1 = 24 df = 24; t table = 1.711 Step 6 Compare! 2.45 > 1.711
Step by Step... Step 7 & 8 t(24) = 2.45, p<0.05 t represents the test statistic that was used 24 is the number of degree of freedom 2.45 is the obtained value (t hitung) 1.711 is the table value (t table) p<0.05 is LoS H1 more attractive than H0 H1 diterima
Time to practice!! Apakah perbedaan antara t-test independent means dan t-test dependent means? Kapan menggunakannya? Data set Ch. 10