WordPress is injected with Google Analysis Code,
1. Select Appearance-> Editor
2. Find footer. php (not always footer every time. If not, check the header and content)
3. Find the base64 encoded string as follows:
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
4. If the problem persists, add comments to other theme files to determine which file google Ad is injected.
5. Try to switch each plugin