Lab 5

Assignment link

1.1 and 1.2

95% CI formula again: \(mean \pm 1.96\frac{standard\ deviation}{number\ of\ observation}\)

library(tidyverse)
icelandic <- read.csv("https://goo.gl/7gIjvK")
icelandic %>% 
  group_by(aspiration, speaker) %>%
  summarise(mean = mean(vowel.dur),
            CI = 1.96*sd(vowel.dur)/sqrt(length(vowel.dur)))

1.3

icelandic %>% 
  group_by(aspiration, speaker) %>%
  summarise(mean = mean(vowel.dur),
            CI = 1.96*sd(vowel.dur)/sqrt(length(vowel.dur))) %>% 
    ggplot(aes(aspiration, mean))+
  geom_point()+
  geom_errorbar(aes(ymin= mean-CI,
                    ymax = mean+CI), width = 0.3)+
  facet_wrap(~speaker)+
  labs(title = "Mean vowel duration with 95% confidence interval",
       caption = "Data from (Coretta 2017)")

1.4

icelandic %>% 
  ggplot(aes(vowel.dur, fill = aspiration, color = aspiration))+
  geom_density(alpha = 0.4)+
  geom_rug()+
  facet_wrap(~speaker)+
  labs(title = "Vowel duration density plot",
       caption = "Data from (Coretta 2017)",
       x = "vowel duration")

icelandic %>% 
  ggplot(aes(sample = vowel.dur, color = aspiration))+
  geom_qq()+
  facet_wrap(~speaker, scales = "free")+
  labs(title = "Vowel duration density plot",
       caption = "Data from (Coretta 2017)")

1.6-1.10

table(icelandic$speaker)

## 
## brs02 bte03  jj04 shg05  tt01 
##   163   157   151   160   175

icelandic_1 <- subset(icelandic,speaker == "brs02")
icelandic_2 <- subset(icelandic,speaker == "bte03")
icelandic_3 <- subset(icelandic,speaker == "jj04")
icelandic_4 <- subset(icelandic,speaker == "shg05")
icelandic_5 <- subset(icelandic,speaker == "tt01")
t.test.results_1 <- t.test(vowel.dur~aspiration, icelandic_1)
t.test.results_2 <- t.test(vowel.dur~aspiration, icelandic_2)
t.test.results_3 <- t.test(vowel.dur~aspiration, icelandic_3)
t.test.results_4 <- t.test(vowel.dur~aspiration, icelandic_4)
t.test.results_5 <- t.test(vowel.dur~aspiration, icelandic_5)