Test statistic - Hypothesis like, definition, opposite, question, Because

simeezee

Hi guys,

I would like to ask a question about "test statistic" definition in Hypothesis reading

as stated in the reading, test statistic = (sample stat - value of the pop parameter under Ho) / (std error of the sample stat)

I was wondering why it's not the opposite. I would have defined it like this
test statistic = (value of the pop parameter under Ho - sample stat) / (std error of the sample stat)

Because in a way, the normal distribution (say if the statistic is the mean) here is the distribution of the sample mean. So its parameters are:
- sample mean
- standard error of the sample mean

if we want to calculate z , it's z = (x - sample mean)/standard error and not (sample mean - x)/ standard error

May be I'm dumb, but I find that Hypothesis reading is a list of recipes to follow, without any good explanations.

that for your help