Purpose Study “Next Stage Purpose” Results

MLQ w/o searching for purpose questions

setwd("/Users/levibrackman/Desktop/Adult_study")
data_pre <- read.csv("pre.csv")
data_post <- read.csv("post.csv")

table(data_pre$GROUP, dnn = "group")

## group
##  0  1 
## 35 32

data <- merge(data_pre, data_post, by = "ID", all = TRUE)

library(psych)
library(lattice)


# Only the Purpose questions in MLQ leaving out the searching for purpose
data$T1MLQP <- apply(data[, c("MLQ1.x", "MLQ4.x", "MLQ5.x", "MLQ6.x")], 1, mean, 
    na.rm = TRUE)
data$T2MLQP <- apply(data[, c("MLQ1.y", "MLQ4.y", "MLQ5.y", "MLQ6.y")], 1, mean, 
    na.rm = TRUE)

plot(data$T1MLQP, data$T2MLQP, ylab = "Pre", xlab = "Post", main = "Purpose")

# pre test plots
bwplot(GROUP.x ~ T1MLQP, ylab = "GROUP", xlab = "MLQ", main = "Pre test", data = data)

# post test plots
bwplot(GROUP.x ~ T2MLQP, ylab = "Group", xlab = "MLQ", main = "Post test", data = data)

# Pre test
t.test(T1MLQP ~ GROUP.x, data = data)

## 
##  Welch Two Sample t-test
## 
## data:  T1MLQP by GROUP.x
## t = 0.5601, df = 62.97, p-value = 0.5774
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -0.4494  0.7994
## sample estimates:
## mean in group 0 mean in group 1 
##           4.800           4.625

t.test(T2MLQP ~ GROUP.x, data = data)

## 
##  Welch Two Sample t-test
## 
## data:  T2MLQP by GROUP.x
## t = -3.155, df = 43.67, p-value = 0.002907
## alternative hypothesis: true difference in means is not equal to 0
## 95 percent confidence interval:
##  -1.4581 -0.3212
## sample estimates:
## mean in group 0 mean in group 1 
##           5.087           5.976

# Ancova, Model for MLQ
MLQP_ANCOVA <- lm(T2MLQP ~ as.factor(GROUP.x) + T1MLQP, data = data)
# check assumptions visually
plot(MLQP_ANCOVA)

# see results
summary(MLQP_ANCOVA)

## 
## Call:
## lm(formula = T2MLQP ~ as.factor(GROUP.x) + T1MLQP, data = data)
## 
## Residuals:
##     Min      1Q  Median      3Q     Max 
## -1.4109 -0.3766  0.0569  0.4157  1.2867 
## 
## Coefficients:
##                     Estimate Std. Error t value Pr(>|t|)    
## (Intercept)           2.1085     0.4777    4.41  6.5e-05 ***
## as.factor(GROUP.x)1   0.9194     0.2047    4.49  5.0e-05 ***
## T1MLQP                0.5968     0.0917    6.51  6.1e-08 ***
## ---
## Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1
## 
## Residual standard error: 0.697 on 44 degrees of freedom
##   (22 observations deleted due to missingness)
## Multiple R-squared:  0.582,  Adjusted R-squared:  0.563 
## F-statistic: 30.6 on 2 and 44 DF,  p-value: 4.66e-09