A variation of the standard definition of Kendall correlation coefficient is necessary in
order to deal with data samples with tied ranks. It known as the Kendall’s tau-bcoefficient and is more effective in determining whether two non-parametric data samples with ties are correlated.
In hypothesis testing, a type II error is due to a failure of rejecting
an invalid null hypothesis. The probability of avoiding a type II error is
called the power of the hypothesis test, and is denoted by the quantity
1 - β.