Experimental design

Investigation that has been repeated

• Valid

• Reliable

Large sample size, so representative of general population

• Valid

• Reliable

Samples have been randomly assigned

• valid

• reilable

A control group has been included

• valid

• reliable

Repetition _______________ the effect of outliers and allows them to be removed.

• increases

• minimises

• equals

• justifies

Can results be reliable without being valid

• True

• False

Which best describes the target?

• Precise, but not accurate

• Accurate but not precise

• Precise and accurate

• Neither accurate nor precise

Measurements: 24.9, 25.2, 25.1, 24.8

True Value: 25.0

These measurements are…

• Accurate, but not precise

• Precise, but not accurate

• Both precise and accurate

• Neither precise nor accurate