Avoid confounding Confounding is the complete mixing of two or more variables. You cannot tell which variable is the cause of any changes if there is confounding. To study the effect of watching TV on aggressive behavior in children. Children from one class watch a TV program. Children from a second class read a book.
Every participant has an equal chance of being in any group.
Statistical analysis gives us some indication of how much random variability to expect Results that exceed the magnitude expected by chance alone are called statistically significant. To obtain informed consent 2. To minimize deception 3.