Definition of two-tailed in English:

two-tailed

adjective

Statistics
  • (of a test) testing for deviation from the null hypothesis in both directions.

    • ‘All tests were two-tailed, and statistical significance was considered for p [is less than] 0.05.’
    • ‘In all the statistical analyses, two-tailed tests and a significance level of p [is less than or equal to].05 were used.’
    • ‘All tests are two-tailed, and statistical significance is considered at P < 0.05.’
    • ‘All statistical significance tests were two-tailed and performed at the 5% level.’
    • ‘Statistical tests were two-tailed and significance levels of alpha = 0.05 were used.’

Pronunciation:

two-tailed

/ˌto͞oˈtāld/