Questa è una vecchia versione del documento. It contains one or more snippets which may be outdated. Any outdated snippets have already been inserted. Replace outdated snippets in this Old Revision?Yes No
Per meglio comprendere i risultati, diamo un nome comprensibile agli items della scala:
# nomi degli itemsnames(items24)<-c(ST24Q01="only if I have to",
ST24Q02="one of my favorite hobbies",
ST24Q03="like talking about b",
ST24Q04="hard to finish b",
ST24Q05="happy receving b as a present.",
ST24Q06="a waste of time",
ST24Q07="enjoy bookstore",
ST24Q08="to get information",
ST24Q09="cannot sit still and read",
ST24Q10="like express opinions about b",
ST24Q11="like exchange b")
La funzione likert() organizza i risultati per tutti gli item di una scala:
likert(items24)
## Item Strongly disagree Disagree Agree Strongly agree
## 1 only if I have to 22.82298 35.90570 30.53855 10.732772
## 2 one of my favorite hobbies 20.32308 36.32162 31.93453 11.420770
## 3 like talking about b 21.24927 33.74201 35.96325 9.045464
## 4 hard to finish b 24.95877 40.39249 26.50886 8.139890
## 5 happy receving b as a present. 19.28187 27.65288 40.17350 12.891747
## 6 a waste of time 42.24040 40.64689 10.97568 6.137024
## 7 enjoy bookstore 17.84124 33.37107 36.88333 11.904361
## 8 to get information 14.98106 35.41769 35.75990 13.841359
## 9 cannot sit still and read 33.11719 43.12805 16.91875 6.836012
## 10 like express opinions about b 13.53650 27.53867 43.82185 15.102982
## 11 like exchange b 22.51850 33.02265 32.07993 12.378918
## Item low neutral high mean sd
## 10 like express opinions about b 41.07516 0 58.92484 2.604913 0.9009968
## 5 happy receving b as a present. 46.93475 0 53.06525 2.466751 0.9446590
## 8 to get information 50.39874 0 49.60126 2.484616 0.9089688
## 7 enjoy bookstore 51.21231 0 48.78769 2.428508 0.9164136
## 3 like talking about b 54.99129 0 45.00871 2.328049 0.9090326
## 11 like exchange b 55.54115 0 44.45885 2.343193 0.9609234
## 2 one of my favorite hobbies 56.64470 0 43.35530 2.344530 0.9277495
## 1 only if I have to 58.72868 0 41.27132 2.291811 0.9369023
## 4 hard to finish b 65.35125 0 34.64875 2.178299 0.8991628
## 9 cannot sit still and read 76.24524 0 23.75476 1.974736 0.8793028
## 6 a waste of time 82.88729 0 17.11271 1.810093 0.8611554
Il centro (“neutral”) è pari a $(\text{nlevels}-1)/2 + 1$, (in questo caso = 2,5), ma può essere cambiato indicando un valore per l'argomento center, ad esempio:
Di default, gli item vengono ordinati per numero di rispondenti con punteggi alti.
Nota: Gli items “only if I have to”, “hard to finish b(ooks)”, “a waste of time”, “cannot sit still and read” hanno polarità invertita.
Vedi Scale Likert: inversione delle polarità
Grafici
Il pacchetto permette di ottenere dei grafici immediatamente utilizzabili per la valutazione delle scale:
## Group Item low neutral high mean sd
## 1 Canada only if I have to 60.82666 0 39.17334 2.277647 1.0001779
## 2 Canada one of my favorite hobbies 61.96628 0 38.03372 2.246538 0.9946381
## 3 Canada like talking about b 56.91068 0 43.08932 2.274789 0.9467191
## 4 Canada hard to finish b 71.77194 0 28.22806 2.054269 0.9211851
## 5 Canada happy receving b as a present. 50.13961 0 49.86039 2.384124 0.9730841
## 6 Canada a waste of time 75.72334 0 24.27666 1.944880 0.9748120
Dal momento che si tratta di un dataframe, possiamo selezionare nell'output le righe che ci interessano:
## Group Item low neutral high mean sd
## 1 Mexico only if I have to 58.64345 0 41.35655 2.273828 0.8912875
## 2 Mexico one of my favorite hobbies 51.68973 0 48.31027 2.435652 0.8726738
## 3 Mexico like talking about b 53.23017 0 46.76983 2.372041 0.8832303
## 4 Mexico hard to finish b 61.01569 0 38.98431 2.258031 0.8783913
## 5 Mexico happy receving b as a present. 42.95741 0 57.04259 2.557262 0.9165585
## 6 Mexico a waste of time 88.39568 0 11.60432 1.699286 0.7521860
## 7 Mexico enjoy bookstore 53.62138 0 46.37862 2.385802 0.8478312
## 8 Mexico to get information 43.57975 0 56.42025 2.605979 0.8836237
## 9 Mexico cannot sit still and read 76.99317 0 23.00683 1.973779 0.8196108
## 10 Mexico like express opinions about b 36.67250 0 63.32750 2.689749 0.8728100
## 11 Mexico like exchange b 51.74623 0 48.25377 2.430137 0.9344254
La funzione non consente di cambiare l'ordinamento per le scale con gruppi, ma è possibile farlo a partire dal risultato:
## Group Item low neutral high mean sd
## 1 Canada like express opinions about b 46.59327 0 53.40673 2.495512 0.9272673
## 2 Canada enjoy bookstore 48.26595 0 51.73405 2.480138 1.0038762
## 3 Canada happy receving b as a present. 50.13961 0 49.86039 2.384124 0.9730841
## 4 Canada like talking about b 56.91068 0 43.08932 2.274789 0.9467191
## 5 Canada like exchange b 59.59525 0 40.40475 2.238699 0.9930502
## 6 Canada only if I have to 60.82666 0 39.17334 2.277647 1.0001779
library(tidyverse)library(likert)data(pisaitems)# selezioniamo una sola scala come esempio
items24 <- pisaitems %>%
select_at(vars(starts_with("ST24Q")))# nomi degli itemsnames(items24)<-c(ST24Q01="only if I have to",
ST24Q02="one of my favorite hobbies",
ST24Q03="like talking about b",
ST24Q04="hard to finish b",
ST24Q05="happy receving b as a present.",
ST24Q06="a waste of time",
ST24Q07="enjoy bookstore",
ST24Q08="to get information",
ST24Q09="cannot sit still and read",
ST24Q10="like express opinions about b",
ST24Q11="like exchange b")
likert(items24)
l24 <- likert(items24)str(l24)summary(l24)## # qui non ha senso, perché le alternative sono solo 4## summary(l24, center = 2)summary(l24)%>%
LabRS::kabbit(digits =2,
col.names=c("Item", "basso", "neutro", "alto", "media", "sd"),
caption ="Statistiche riassuntive: output")plot(l24)# con colori e titolocol<-colorRampPalette(c("pink", "white", "blue"))(4)plot(l24, colors=col)+
labs(title="Reading Attitudes")plot(l24, type='heat', wrap=30, text.size=3.5)# variabile di raggruppamento
l24g <- likert(items24, grouping=pisaitems$CNT)summary(l24g)%>%head()summary(l24g)%>%filter(Group =="Mexico")summary(l24g)%>%
arrange(Group, desc(high))%>%head()plot(l24g, group.order=c('Mexico', 'Canada', 'United States'))
