Reading speed

HW Exercise 0316-5

Ten subjects read a paragraph consisting of seven sentences. The reading time (in seconds) for each sentence was the outcome measure. The predictors are the serial position of the sentence (Sp), the number of words in the sentences (Wrds), and the number of new arguments in the sentence (New). (a) Rank subjects by their reading speeed (b) Estimate, on average, how long does it take to read a word.

Loading and checking the dataset

dta <- read.table("C:/Users/USER/Desktop/R_data management/0316/readingtimes.txt", header = T)
head(dta)

##   Snt Sp Wrds New   S01   S02   S03   S04   S05    S06    S07   S08   S09   S10
## 1   1  1   13   1 3.429 2.795 4.161 3.071 3.625  3.161  3.232 7.161 1.536 4.063
## 2   2  2   16   3 6.482 5.411 4.491 5.063 9.295  5.643  8.357 4.313 2.946 6.652
## 3   3  3    9   2 1.714 2.339 3.018 2.464 6.045  2.455  4.920 3.366 1.375 2.179
## 4   4  4    9   2 3.679 3.714 2.866 2.732 4.205  6.241  3.723 6.330 1.152 3.661
## 5   5  5   10   3 4.000 2.902 2.991 2.670 3.884  3.223  3.143 6.143 2.759 3.330
## 6   6  6   18   4 6.973 8.018 6.625 7.571 8.795 13.188 11.170 6.071 7.964 7.866

1. Rank subjects by their reading speeed

Sp<-colMeans(dta)
Sp<-sort(Sp[-(1:4)])
Sp

##      S09      S03      S04      S02      S01      S10      S08      S07 
## 2.741000 3.774286 3.779286 3.847000 4.130143 4.493714 5.011429 5.228429 
##      S06      S05 
## 5.371286 5.620000

barplot(Sp, xlab="Subjects", ylab="Average reading time", col=viridis::viridis(10))

2. Estimate, on average, how long does it take to read a word per-person.

colSums(dta[5:14])/colSums(dta[3])

##       S01       S02       S03       S04       S05       S06       S07       S08 
## 0.3569259 0.3324568 0.3261728 0.3266049 0.4856790 0.4641852 0.4518395 0.4330864 
##       S09       S10 
## 0.2368765 0.3883457

average time to read a word

mean(colSums(dta[5:14])/colSums(dta[3]))

## [1] 0.3802173