**INFORMATION:**

I am analysing a dataset in which there I have the following data of 50 participants:

Intervention: yes/no

T0: bacterial counts at T0 in cfu/ml (baseline value)

T12: bacterial counts at T12 in cfu/ml (after 12 months)

The data for bacterial counts are for Total bacterial counts (TBC), as well as for specific bacteria within the TBC.

I'm trying to find out the effect of the intervention after 12 months (is it effective?).

The TBC ranges from 0 cfu/ml (no bacteria detected) tot a maximum of 400000 cfu/ml.

**QUESTION 1:**

I am thinking of using a Two-way mixed ANOVA, with the intervention as 'between-groups-variable', and the time at which the sample is taken as 'repeated-measures-variable'. Is this the right test to answer the question of this research?

**QUESTION 2:**

In order to normalise the raw data (which is heavily skewed), I am transforming my data using Log10. However, the '0 cfu/ml' values are not transformed, and if I add them manually (either 0 or 1 (log(1)=0)) they are either outliers (in variables where I have a few 0 cfu/ml values), or the data again is skewed heavily in variables where there are a lot of 0-values. So how do I deal with these 0-values in achieving normality?

Please inquire after any additional information you might need in order to help me!

Thank you in advance,

Regards,

Lucas