In wireless communications, trustworthiness computation has emerged as a crucial aspect of safeguarding modern systems against cybersecurity threats, ensuring reliable data transmission and upholding user trust. However, there is no unified definition of trustworthiness computation in the literature, and it is often presented as a specifically tailored adaptation of attack detection mechanisms. In contrast, this work introduces a general method for trustworthiness computation in wireless networks. It leverages key system characteristics, such as the channel, timing, and packet information to identify measurable Quality of Service (QoS) features with sufficient sensitivity across varying operational conditions.  Building on these features, a novel three-step approach is applied. It employs changepoint detection to identify potential trustworthiness issues, calculates indicators based on the observed features, and finally combines them into a quantitative representation of trustworthiness. This systematic method effectively distinguishes between regular statistical variations in QoS features and actual trustworthiness issues. The applicability of the presented approach is demonstrated using a typical IEEE 802.11 wireless link, where different QoS features and scenarios are defined. These scenarios include network attacks, system malfunctions, and typical operational conditions.  Our trustworthiness computation method correctly alerts the system to all trustworthiness issues that we challenge it with.