Turbulence intensity levels are assigned different values according to set a probability distribution. Many researchers do not consider probability distributions when determining turbulence intensity levels. This is one cause of the disagreement between numerical simulations of turbulence modeling and experimental data. This study focuses on the use of weighted statistics to evaluate turbulence intensity levels through three types of examples. The first is a hands-on example with a Pitot-static tube. The second utilizes numerical data and the Monte Carlo method. The third relies on a dataset by constant temperature anemometry and laser Doppler anemometry, available from the literature. This study finds that turbulence intensity evaluations differ depending on the selection of the probability distribution. The turbulence intensity according to a Gaussian distribution is reduced by more than 30% in comparison with that set with a rectangular distribution. The notion of the true and engineering turbulence intensity is introduced.