Assignment 4 - Question 2

Research Question

Is there a relationship between hours of sleep and hours of phone use?

Import the Data

q2 <- read_excel("A4Q2.xlsx")
head(q2)

## # A tibble: 6 × 2
##   sleep  phone
##   <dbl>  <dbl>
## 1  9.03  1.78 
## 2  6.76  6.62 
## 3  9.18  0.289
## 4  7.20  3.33 
## 5  3    10    
## 6  6.71  4.24

Test Selection

A Spearman rank-order correlation was selected because hours of sleep and hours of phone use are continuous variables, but both variables violated the normality assumption.

Normality Tests

shapiro.test(q2$sleep)

## 
##  Shapiro-Wilk normality test
## 
## data:  q2$sleep
## W = 0.91407, p-value = 8.964e-08

shapiro.test(q2$phone)

## 
##  Shapiro-Wilk normality test
## 
## data:  q2$phone
## W = 0.89755, p-value = 9.641e-09

The Shapiro-Wilk tests were statistically significant for both variables, indicating that the data were not normally distributed.

Spearman Correlation

cor.test(q2$sleep, q2$phone, method = "spearman", exact = FALSE)

## 
##  Spearman's rank correlation rho
## 
## data:  q2$sleep and q2$phone
## S = 908390, p-value < 2.2e-16
## alternative hypothesis: true rho is not equal to 0
## sample estimates:
##        rho 
## -0.6149873

Interpretation

A Spearman rank-order correlation showed a statistically significant moderate negative relationship between hours of sleep and hours of phone use, r_s = -.615, p < .001. This means that, in this dataset, greater phone use was associated with fewer hours of sleep.