diff --git a/README.md b/README.md
index 4c9503f..f8ed191 100644
--- a/README.md
+++ b/README.md
@@ -188,7 +188,7 @@ With those Classifiers, the hypothesis can be proven, that a classifier is able
     Besides that, older people are more likely to receive medical support such as medication and pacemakers which can prevent sinus bradycardia or at least lower its effect. 
     The sample size in the study conducted may also play a role in the significance of the frequency.
 
-### Noise reduction
+## Noise reduction
 Noise suppression was performed on the existing ECG data. A three-stage noise reduction was performed to reduce the noise in the ECG signals. First, a Butterworth filter was applied to the signals to remove the high frequency noise. Then a Loess filter was applied to the signals to remove the low frequency noise. Finally, a non-local-means filter was applied to the signals to remove the remaining noise.
 
 How the noise reduction was performed in detail can be seen in the following notebook: [noise_reduction.ipynb](notebooks/noise_reduction.ipynb)