assignment6q1

library(readxl)
library(ggpubr)

## Loading required package: ggplot2

library(effectsize)
library(rstatix)

## 
## Attaching package: 'rstatix'

## The following objects are masked from 'package:effectsize':
## 
##     cohens_d, eta_squared

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

data1 <- read_excel("A6Q1.xlsx")

#Creating Groups for Before and After

Before <- data1$Before
After <- data1$After

Differences <- After - Before

#Calculate the mean, standard deviation, median for the scores for each of your two groups.

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

#Creating Histogram

hist(Differences,
     main = "Histogram of body weight before and after",
     xlab = "body weight",
     ylab = "before and after",
     col = "blue",
     border = "black",
     breaks = 20)

boxplot(Differences,
        main = "Distribution of weights (After - Before)",
        ylab = "before and after diet change ",
        col = "blue",
        border = "darkblue")

#Boxplot #There are not dots outside the boxplot. #The dots [are / are not] close to the whiskers. #The dots [are / are not] very far away from the whiskers. #Based on these findings, the boxplot is [normal / not normal]

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 = .3318).

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

#A Dependent T-Test was conducted to determine if there was a difference in weight before the diet versus after the diet. #Before scores (M = 76.13, SD = 7.78) were [significantly / not significantly] different from after scores (M = 71.58 , SD = 6.63), t(df#) = 19 , p = 0.072.