Pendugaan Parameter Proporsi dan Varians (Ragam) Pertemuan 14 Matakuliah: L0104 / Statistika Psikologi Tahun : 2008

Bina Nusantara Learning Outcomes 3 Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Mahasiswa akan dapat menghitung pendugaan parameter proporsi satu dan dua populasi, varians/Ragam dan rasio dua varians/ragam populasi.

Bina Nusantara Outline Materi 4 Pendugaan proporsi satu populasi Pendugaan beda dua proporsi Pendugaan varians satu populasi Pendugaan rasio dua varians

Bina Nusantara Interval Estimation of a Population Proportion Interval Estimate where: 1 -α is the confidence coefficient zα/2 is the z value providing an area of cd /2 in the upper tail of the standard normal probability distribution is the sample proportion

Bina Nusantara Interval Estimate of a Population Proportion where: n = 500, = 220/500 =.44, z  /2 = PSI is 95% confident that the proportion of all voters that favors the candidate is between.3965 and Contoh Soal: Political Science, Inc.

Bina Nusantara Sample Size for Interval Estimate of a Population Proportion At 99% confidence, z. 005 = Note: We used.44 as the best estimate of p in the above expression. If no information is available about p, then.5 is often assumed because it provides the highest possible sample size. If we had used p =.5, the recommended n would have been Contoh Soal: Political Science, Inc.

Bina Nusantara Inferences About Population Variances Inference about a Population Variance Inferences about the Variances of Two Populations

Bina Nusantara Inferences About a Population Variance Chi-Square Distribution Interval Estimation of σ  2 Hypothesis Testing

Bina Nusantara Interval Estimation of σ2 Interval Estimate of a Population Variance where the    values are based on a chi-square distribution with n - 1 degrees of freedom and where 1 - α is the confidence coefficient.

Bina Nusantara Interval Estimation of σ  Interval Estimate of a Population Standard Deviation Taking the square root of the upper and lower limits of the variance interval provides the confidence interval for the population standard deviation.

Bina Nusantara Chi-Square Distribution With Tail Areas of % of the possible  2 values 95% of the possible  2 values 22 2 Interval Estimation of σ  2

Bina Nusantara Example: Buyer’s Digest Interval Estimation of σ2 n - 1 = = 9 degrees of freedom and a =.05 22 2

Bina Nusantara Interval Estimation of σ 2 n - 1 = = 9 degrees of freedom and a =.05 22 2 Example: Buyer’s Digest Area in Upper Tail =.975

Bina Nusantara Example: Buyer’s Digest Interval Estimation of σ 2 n - 1 = = 9 degrees of freedom and a =.05 22 22 0 0 Area in Upper Tail =.025 Area in Upper Tail =

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