chi-square test VS T-test

[chi-square test VS T-test]- purpose

1. chi-square test

   • Determine if the different in results is due to chance or other factors

2. T -test

   • test the significance of differences between the Mean Between 2 unpaired samples

[chi-square test VS T-test]- what to do

1. chi-square test

   • Compare actual observed results with expected result (expected ratio)

2. T -test

   • Comparison of mean between 2 unpaired samples

[chi-square test VS T-test]- list the expected ratios

1. chi-square test

   • yes

2. T -test

   • no

[chi-square test VS T-test]- determine df

1. chi-square test

   • df = n-1 (no. of phenotypic groups)

2. T -test

   • df = n1 + n2 -2 (no. of samples)

[chi-square test VS T-test]- how to determine p?

1. chi-square test

   • x² distribution table

2. T -test

   • t-distribution table

reject H0 or not?

at 5% level of significance

• p greater than 0.05 = do not reject H0 (difference not significant)

• p smaller than 0.05 = do not reject H0 (difference is significant)