Chi-squared

• what type of test is the chi-squared test

  a statistical test
• what is the chi-squared test\?

  a statistical test which can be used to establish whether the difference between observed and expected results is small enough to occur purely due to chance.
• the chi-squared test can be used to test

  the NULL hypothesis
• what is a null hypothesis

  a hypothesis in which the results of a scientific investigation will produce no statistical significance
• what criteria must be met

  • sample size must be sufficiently large enough , over 20
  • data that falls into discrete categories ONLY
  • only RAW COUNTS (no %, rates etc)
• the value obtained from the chisquared test is compared to what

  the critical value
• in chi square what is the critical value

  p = 0.05
• when is the null hypothesis ACCEPTED ?

  When the value obtained is equal to or greater than the critical value

  • as the difference due to chance is NOT SIGNIFICANT
• How to work out Degrees of freedom

  number of categories - 1
• when is the null hypothesis rejected?

  When the value is less than the critical value
• null hypothesis rejected- what does this mean?

  observed and expected results is not due to chance, as is significant.