\documentclass{article}
\usepackage[active,tightpage]{preview}
\usepackage{varwidth}
\usepackage{pgfplots}
\begin{document}
\begin{preview}
\begin{varwidth}{18cm}
\centering
\begin{tabular}{cc}
\multicolumn{2}{c}{\textbf{
Transfusion
 Dataset}} \\

\begin{tikzpicture}
\begin{axis}[ 
	title = \textbf{Decision Tree},
	ylabel=Accuracy,
	grid=both,
 	height=5cm, width=8.0cm, 
 	legend pos=south east, 
 	minor tick num = 1,
	xtick={1, 2, 3, 4},
	cycle list={{gray,line width=1.5pt},{black,line width=1.5pt},}
	]
\addplot+[error bars/.cd, x dir=none, x fixed relative=0.5, y dir=both,y explicit relative,]
table[x=features,y=PCA,y error=PCA_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.714840	0.003966	0.712914	0.004831
2	0.710615	0.004071	0.716176	0.004455
3	0.729332	0.004015	0.716364	0.004884
4	0.724866	0.003652	0.725989	0.003514
};
\addplot+[error bars/.cd,
x dir=none, x fixed relative=0.5,
y dir=both,y explicit relative,
]
table[x=features,y=BDPC,y error=BDPC_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.714840	0.003966	0.712914	0.004831
2	0.710615	0.004071	0.716176	0.004455
3	0.729332	0.004015	0.716364	0.004884
4	0.724866	0.003652	0.725989	0.003514
};
\end{axis}
\end{tikzpicture}
&
\begin{tikzpicture}
\begin{axis}[ 
	title = \textbf{k-NN},
	grid=both,
 	height=5cm, width=8.0cm, 
 	legend pos=south east, 
 	minor tick num = 1,
	xtick={1, 2, 3, 4},
	cycle list={{gray,line width=1.5pt},{black,line width=1.5pt},}
	]
\addplot+[error bars/.cd, x dir=none, x fixed relative=0.5, y dir=both,y explicit relative,]
table[x=features,y=PCA,y error=PCA_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.688396	0.005072	0.671337	0.005321
2	0.693422	0.004881	0.680882	0.005181
3	0.697166	0.005061	0.693209	0.005065
4	0.697166	0.005061	0.697193	0.005050
};
\addplot+[error bars/.cd,
x dir=none, x fixed relative=0.5,
y dir=both,y explicit relative,
]
table[x=features,y=BDPC,y error=BDPC_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.688396	0.005072	0.671337	0.005321
2	0.693422	0.004881	0.680882	0.005181
3	0.697166	0.005061	0.693209	0.005065
4	0.697166	0.005061	0.697193	0.005050
};
\end{axis}
\end{tikzpicture}
\\
\begin{tikzpicture}
\begin{axis}[ 
	title = \textbf{Linear Discriminant},
	xlabel=Number of extracted features, 
	ylabel=Accuracy,
	grid=both,
 	height=5cm, width=8.0cm, 
 	legend pos=south east, 
 	minor tick num = 1,
	xtick={1, 2, 3, 4},
	cycle list={{gray,line width=1.5pt},{black,line width=1.5pt},}
	]
\addplot+[error bars/.cd, x dir=none, x fixed relative=0.5, y dir=both,y explicit relative,]
table[x=features,y=PCA,y error=PCA_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.766390	0.001277	0.766150	0.001260
2	0.770802	0.001708	0.765802	0.001171
3	0.772353	0.001629	0.768636	0.001855
4	0.772353	0.001629	0.772353	0.001629
};
\addplot+[error bars/.cd,
x dir=none, x fixed relative=0.5,
y dir=both,y explicit relative,
]
table[x=features,y=BDPC,y error=BDPC_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.766390	0.001277	0.766150	0.001260
2	0.770802	0.001708	0.765802	0.001171
3	0.772353	0.001629	0.768636	0.001855
4	0.772353	0.001629	0.772353	0.001629
};
\end{axis}
\end{tikzpicture}
&
\begin{tikzpicture}
\begin{axis}[ 
	title = \textbf{Naive Bayes},
	xlabel=Number of extracted features, 
	grid=both,
 	height=5cm, width=8.0cm, 
 	legend pos=south east, 
 	minor tick num = 1,
	xtick={1, 2, 3, 4},
	cycle list={{gray,line width=1.5pt},{black,line width=1.5pt},}
	]
\addplot+[error bars/.cd, x dir=none, x fixed relative=0.5, y dir=both,y explicit relative,]
table[x=features,y=PCA,y error=PCA_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.767567	0.001568	0.763503	0.001397
2	0.769545	0.001543	0.758476	0.004538
3	0.789011	0.002643	0.762620	0.005099
4	0.777781	0.004550	0.777781	0.004550
};
\addplot+[error bars/.cd,
x dir=none, x fixed relative=0.5,
y dir=both,y explicit relative,
]
table[x=features,y=BDPC,y error=BDPC_conf]{
features	PCA	PCA_conf	BDPC	BDPC_conf
1	0.767567	0.001568	0.763503	0.001397
2	0.769545	0.001543	0.758476	0.004538
3	0.789011	0.002643	0.762620	0.005099
4	0.777781	0.004550	0.777781	0.004550
};
\legend{PCA, Proposed}
\end{axis}
\end{tikzpicture}
\end{tabular}
\end{varwidth}
\end{preview}
\end{document}
