library(readxl)
library(ggpubr)

## Loading required package: ggplot2

library(effsize)
library(rstatix)

## 
## Attaching package: 'rstatix'

## The following object is masked from 'package:stats':
## 
##     filter

A6Q1 <- read_excel("//apporto.com/dfs/SLU/Users/hannahsmith3_slu/Downloads/A6Q1.xlsx")

Before <- A6Q1$Before
After <- A6Q1$After

Differences <- After - Before

mean(Before, na.rm = TRUE)

## [1] 76.13299

median(Before, na.rm = TRUE)

## [1] 75.95988

sd(Before, na.rm = TRUE)

## [1] 7.781323

mean(After, na.rm = TRUE)

## [1] 71.58994

median(After, na.rm = TRUE)

## [1] 70.88045

sd(After, na.rm = TRUE)

## [1] 6.639509

hist(Differences, 
     breaks = 15, 
    col = "blue", 
    border = "white")

#Data for the difference scores appears normally distrubuted. 

boxplot(Differences, 
        main = "Distribution of Score Differences (After - Before", 
        ylab = "Difference in Scores", 
        col = "blue", 
        border = "darkblue")

#The difference scores boxplot does have one outlier.

shapiro.test(Differences)

## 
##  Shapiro-Wilk normality test
## 
## data:  Differences
## W = 0.94757, p-value = 0.3318

#Shapiro-Wilk Difference Scores 
#The data is normally distributed, (p = .33)

t.test(Before, After, paired = TRUE, 
       na.action = na.omit)

## 
##  Paired t-test
## 
## data:  Before and After
## t = 1.902, df = 19, p-value = 0.07245
## alternative hypothesis: true mean difference is not equal to 0
## 95 percent confidence interval:
##  -0.4563808  9.5424763
## sample estimates:
## mean difference 
##        4.543048

cohen.d(Before, After, paired = TRUE) 

## 
## Cohen's d
## 
## d estimate: 0.6284306 (medium)
## 95 percent confidence interval:
##      lower      upper 
## -0.1035207  1.3603820

#A dependent t-test was conducted to determine if there was a difference in weight between Before and After scores.
#Before scores(M = 76.13, SD = 7.78) were significantly different from After scores(M = 71.59 , SD = 6.64), t(19) = 6.14, p-value > .05. 
#The effect size was medium, Cohen's d = .63.