Submitted by: Radhika Kapoor
Group work with: Madi Bunderson, Catie Connolly, Jamie Mitchell
For this exercise, please try to reproduce the results from Experiment 2 of the associated paper (de la Fuente, Santiago, Roman, Dumitrache, & Casasanto, 2014). The PDF of the paper is included in the same folder as this Rmd file.
Researchers tested the question of whether temporal focus differs between Moroccan and Spanish cultures, hypothesizing that Moroccans are more past-focused, whereas Spaniards are more future-focused. Two groups of participants (\(N = 40\) Moroccan and \(N=40\) Spanish) completed a temporal-focus questionnaire that contained questions about past-focused (“PAST”) and future-focused (“FUTURE”) topics. In response to each question, participants provided a rating on a 5-point Likert scale on which lower scores indicated less agreement and higher scores indicated greater agreement. The authors then performed a mixed-design ANOVA with agreement score as the dependent variable, group (Moroccan or Spanish, between-subjects) as the fixed-effects factor, and temporal focus (past or future, within-subjects) as the random effects factor. In addition, the authors performed unpaired two-sample t-tests to determine whether there was a significant difference between the two groups in agreement scores for PAST questions, and whether there was a significant difference in scores for FUTURE questions.
Below is the specific result you will attempt to reproduce (quoted directly from the results section of Experiment 2):
According to a mixed analysis of variance (ANOVA) with group (Spanish vs. Moroccan) as a between-subjects factor and temporal focus (past vs. future) as a within-subjectS factor, temporal focus differed significantly between Spaniards and Moroccans, as indicated by a significant interaction of temporal focus and group, F(1, 78) = 19.12, p = .001, ηp2 = .20 (Fig. 2). Moroccans showed greater agreement with past-focused statements than Spaniards did, t(78) = 4.04, p = .001, and Spaniards showed greater agreement with future-focused statements than Moroccans did, t(78) = −3.32, p = .001. (de la Fuente et al., 2014, p. 1685).
library(tidyverse) # for data munging
library(knitr) # for kable table formating
library(haven) # import and export 'SPSS', 'Stata' and 'SAS' Files
library(readxl) # import excel files
library(afex) # anova functions
# #optional packages/functions:
# library(ez) # anova functions 2
#library(scales) # for plotting
#std.err <- function(x) sd(x)/sqrt(length(x)) # standard error
# Just Experiment 2
data_path <- '~/Documents/Stanford readings/251 Experimental methods/Problem sets/problem_sets/ps3/Group B/Choice 3/data/DeLaFuenteEtAl_2014_RawData.xls'
d <- read_excel(data_path, sheet=3)
view(d)
summary(d)
## group participant subscale item
## Length:1680 Min. : 1.00 Length:1680 Length:1680
## Class :character 1st Qu.:10.75 Class :character Class :character
## Mode :character Median :20.50 Mode :character Mode :character
## Mean :20.88
## 3rd Qu.:31.25
## Max. :40.00
## Agreement (0=complete disagreement; 5=complete agreement)
## Min. :1.000
## 1st Qu.:2.000
## Median :3.000
## Mean :3.138
## 3rd Qu.:4.000
## Max. :5.000
colnames(d)
## [1] "group"
## [2] "participant"
## [3] "subscale"
## [4] "item"
## [5] "Agreement (0=complete disagreement; 5=complete agreement)"
unique(d$Agreement)
## NULL
#The data is tidy - each observation is in a row, and values are in columns
summary(d)
## group participant subscale item
## Length:1680 Min. : 1.00 Length:1680 Length:1680
## Class :character 1st Qu.:10.75 Class :character Class :character
## Mode :character Median :20.50 Mode :character Mode :character
## Mean :20.88
## 3rd Qu.:31.25
## Max. :40.00
## Agreement (0=complete disagreement; 5=complete agreement)
## Min. :1.000
## 1st Qu.:2.000
## Median :3.000
## Mean :3.138
## 3rd Qu.:4.000
## Max. :5.000
#identify duplicates
duplicates <- d %>%
arrange(group, participant, subscale, item) %>%
group_by(group, participant, subscale, item) %>%
filter(n()>1)
#d add id column and rename group
d <- d %>%
mutate(id=ifelse(group=="Moroccan",participant,participant+40),
group=ifelse(group=="Moroccan","Moroccan","Spaniards"))
#drop duplicated rows
d_drop <- d %>%
arrange(group, participant,item) %>%
rename(rating= "Agreement (0=complete disagreement; 5=complete agreement)") %>%
distinct(id, group, participant, subscale, item, .keep_all=T)
#average ratings for duplicate rows
##wrote this code but didnt use it, used the version above
d_average <- d %>%
arrange(group, participant,item) %>%
rename(rating= "Agreement (0=complete disagreement; 5=complete agreement)") %>%
group_by(id, group, participant, subscale, item) %>%
summarise(rating=mean(rating)) #mean for all combinations of participant and item
Try to recreate Figure 2 (fig2.png, also included in the same folder as this Rmd file):
datasummary <- d_drop %>%
group_by(group, subscale) %>%
summarise(meanRating = mean(rating),
n= n(),
seRating=sd(rating, na.rm=T)/sqrt(n))
datasummary$group <- factor(datasummary$group, levels=c("Spaniards", "Moroccan"))
view(datasummary)
ggplot(datasummary, aes(x=group, y=meanRating, fill=subscale)) +
geom_bar(position="dodge", stat="identity") +
geom_errorbar(aes(ymin=meanRating-seRating,ymax=meanRating+seRating),width=0.2,position=position_dodge(.9), stat="identity") +
scale_fill_brewer(palette="Set1") +
coord_cartesian(ylim=c(2,4))
According to a mixed analysis of variance (ANOVA) with group (Spanish vs. Moroccan) as a between-subjects factor and temporal focus (past vs. future) as a within-subjects factor, temporal focus differed significantly between Spaniards and Moroccans, as indicated by a significant interaction of temporal focus and group, F(1, 78) = 19.12, p = .001, ηp2 = .20 (Fig. 2).
# reproduce the above results here
d3 <- d_drop %>%
group_by(id, group, participant, subscale) %>%
summarise(rating=mean(rating)) #mean rating by participant for past/future subscale
d3$id <- factor(d3$id)
Within.aov.1 <- aov_car(rating ~ group*subscale + Error(id/subscale), data=d3, anova_table=list(es="pes"), na.rm = TRUE)
summary(Within.aov.1)
##
## Univariate Type III Repeated-Measures ANOVA Assuming Sphericity
##
## Sum Sq num Df Error SS den Df F value Pr(>F)
## (Intercept) 1536.97 1 15.388 76 7591.0606 < 2.2e-16 ***
## group 0.35 1 15.388 76 1.7195 0.1937007
## subscale 3.76 1 37.591 76 7.5937 0.0073282 **
## group:subscale 8.26 1 37.591 76 16.7057 0.0001073 ***
## ---
## Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
knitr::kable(nice(Within.aov.1))
| Effect | df | MSE | F | pes | p.value |
|---|---|---|---|---|---|
| group | 1, 76 | 0.20 | 1.72 | .022 | .194 |
| subscale | 1, 76 | 0.49 | 7.59 ** | .091 | .007 |
| group:subscale | 1, 76 | 0.49 | 16.71 *** | .180 | <.001 |
Moroccans showed greater agreement with past-focused statements than Spaniards did, t(78) = 4.04, p = .001,
# reproduce the above results here
d4 <- d3 %>%
filter(subscale=="PAST")
t.test(rating ~ group, data = d4)
##
## Welch Two Sample t-test
##
## data: rating by group
## t = 3.6595, df = 74.738, p-value = 0.0004684
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## 0.2527584 0.8567987
## sample estimates:
## mean in group Moroccan mean in group Spaniards
## 3.261072 2.706294
and Spaniards showed greater agreement with future-focused statements than Moroccans did, t(78) = −3.32, p = .001.(de la Fuente et al., 2014, p. 1685)
# reproduce the above results here
d4 <- d3 %>%
filter(subscale=="FUTURE")
t.test(rating ~ group, data = d4)
##
## Welch Two Sample t-test
##
## data: rating by group
## t = -3.0635, df = 71.23, p-value = 0.003088
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
## -0.5681658 -0.1201675
## sample estimates:
## mean in group Moroccan mean in group Spaniards
## 3.133333 3.477500
Were you able to reproduce the results you attempted to reproduce? If not, what part(s) were you unable to reproduce?
I could replicate the figures, but the results are a little different for ANOVA and t-test
How difficult was it to reproduce your results?
It was pretty difficult to replicate the inferential statistics
What aspects made it difficult? What aspects made it easy?
- Directions on using ANOVA were not clear (2) Not clear how they handled the duplicate participants (3) The degree of freedom for t-tests I have are not the same as the paper, I am not sure why