Perbandingan model dengan ANOVA

Membandingkan model bisa jadi menantang. Ada banyak metode, meskipun di luar cakupan kursus ini, seperti pemilihan model (misalnya, AIC).

Analysis of Variance (ANOVA) tersedia sebagai opsi dasar untuk membandingkan model lmer. ANOVA menguji apakah satu model menjelaskan lebih banyak variabilitas dibandingkan model lainnya. ANOVA melakukan ini dengan menelaah jumlah variabilitas yang dijelaskan oleh model-model tersebut.

Sebagai contoh, Anda dapat melihat apakah Year memprediksi Crime di Maryland. Untuk melakukannya, bangun model nol yang hanya memuat County sebagai efek-acak dan sebuah model tahun yang memasukkan Year. Anda kemudian dapat membandingkan kedua model menggunakan fungsi anova().

Jika Year menjelaskan jumlah variabilitas yang signifikan, maka nilai P akan lebih kecil daripada ambang yang Anda tetapkan sebelumnya (biasanya 0,05).

Latihan ini adalah bagian dari kursus

Model Hierarki dan Mixed Effects di R

Latihan interaktif praktis

Cobalah latihan ini dengan menyelesaikan kode contoh berikut.

# Build the Null model with only County as a random-effect
null_model <- lmer(Crime ~ (1 | ___) , data = md_crime)

# Build the Year2 model with Year2 as a fixed and random slope and County as the random-effect
year_model <- lmer(Crime ~ ___ + (1 + ___ | ___) , data = md_crime)

# Compare null_model and year_model using an anova
anova(___, ___)

Edit dan Jalankan Kode

Latihan ini adalah bagian dari kursus

Model Hierarki dan Mixed Effects di R

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4.7+

Mulai Kursus Gratis

The first chapter provides an example of when to use a mixed-effect and also describes the parts of a regression. The chapter also examines a student test-score dataset with a nested structure to demonstrate mixed-effects.

Exercise 1: What is a hierarchical model?Exercise 2: Examples of hierarchical datasets Exercise 3: Multi-level student data Exercise 4: Exploring multiple-levels: Classrooms and schools Exercise 5: Parts of a regression Exercise 6: Intercepts Exercise 7: Slopes and multiple regression Exercise 8: Random-effects in regressions with school data Exercise 9: Random-effect intercepts Exercise 10: Random-effect slopes Exercise 11: Building the school model Exercise 12: Interpreting the school model

This chapter providers an introduction to linear mixed-effects models. It covers different types of random-effects, describes how to understand the results for linear mixed-effects models, and goes over different methods for statistical inference with mixed-effects models using crime data from Maryland.

Exercise 1: Model efek campuran linear - Data angka kelahiran Exercise 2: Membangun model lmer dengan efek acak Exercise 3: Menyertakan efek tetap Exercise 4: Kemiringan efek-acak Exercise 5: Kemiringan efek-acak tak berkorelasi Exercise 6: Prediktor efek tetap dan acak Exercise 7: Memahami dan melaporkan keluaran dari lmer Exercise 8: Membandingkan keluaran print dan summary Exercise 9: Mengekstrak koefisien Exercise 10: Menampilkan hasil dari model lmer Exercise 11: Inferensi statistik dengan data kejahatan Maryland Exercise 12: Memvisualisasikan data kejahatan Maryland Exercise 13: Mengubah skala kemiringan (slope)Exercise 14: Pengujian hipotesis nol Exercise 15: Kontroversi seputar P-value Exercise 16: Perbandingan model dengan ANOVA

Latihan Saat Ini

This chapter extends linear mixed-effects models to include non-normal error terms using generalized linear mixed-effects models. By altering the model to include a non-normal error term, you are able to model more kinds of data with non-linear responses. After reviewing generalized linear models, the chapter examines binomial data and count data in the context of mixed-effects models.

Exercise 1: Crash course on GLMs Exercise 2: Logistic regression Exercise 3: Poisson Regression Exercise 4: Plotting GLMs Exercise 5: Binomial data Exercise 6: Toxicology data Exercise 7: Marketing example Exercise 8: Calculating odds-ratios Exercise 9: Count data Exercise 10: Internet click-throughs Exercise 11: Chlamydia by age-group and county Exercise 12: Displaying chlamydia results

This chapter shows how repeated-measures analysis is a special case of mixed-effect modeling. The chapter begins by reviewing paired t-tests and repeated measures ANOVA. Next, the chapter uses a linear mixed-effect model to examine sleep study data. Lastly, the chapter uses a generalized linear mixed-effect model to examine hate crime data from New York state through time.

Exercise 1: An introduction to repeated measures Exercise 2: Paired t-test Exercise 3: Repeated measures ANOVA Exercise 4: Sleep study Exercise 5: Exploring the data Exercise 6: Building models Exercise 7: Comparing regressions and ANOVAs Exercise 8: Plotting results Exercise 9: Hate in NY state?Exercise 10: Exploring NY hate data Exercise 11: Building the model Exercise 12: Interpreting model results Exercise 13: Displaying the results Exercise 14: Hierarchical models in R review Exercise 15: Conclusion