Qualitative data is the data that characterizes and approximates the information. Qualitative data can be observed and recorded. There are multiple ways of collecting qualitative data when you tend to learn on how to write data analysis for dissertation like, one-on-one interviews, observation methods, focus groups etc.
Once you are done with the data collection by interviews and focus groups. Numerous tools can be used for the analysis of your qualitative data. Like, NVivo 11, Atlas.ti, Dedoos, MAXQDA, Quirkos, QDA Miner, Saturate etc.
Inferential statistics testing and all its techniques are incompatible with qualitative data as it is not based on numeric values. However, a quantitative type of data is compatible with statistical tests and techniques. As it is collected in the form of numeric values.