Severity: Warning
Message: fopen(/home/answnniz/public_html/system/sessions/ci_session4c98a9f099d4e4b5260b9578f68172d225b9e9ef): failed to open stream: Disk quota exceeded
Filename: drivers/Session_files_driver.php
Line Number: 176
Backtrace:
File: /home/answnniz/public_html/index.php
Line: 315
Function: require_once
Severity: Warning
Message: session_start(): Failed to read session data: user (path: /home/answnniz/public_html/system/sessions)
Filename: Session/Session.php
Line Number: 143
Backtrace:
File: /home/answnniz/public_html/index.php
Line: 315
Function: require_once
Which one of the following is a principle of experimental design that an observational study does not incorporate? control or comparison randomization use enough subjects gather information without disturbing population