ecommerce Conversion Rate Analysis

Hi,

I don't know if this is the right forum for this, but hopefully someone
can help

I have an ecommerce website selling things on the internet. I have
historical daily data on numbers of users and orders (and so hence
conversion rate). My problem is that I have recently made a change to
my site that I think has increased conversion, but not by such a large
degree that the effect is obvious. Average daily conversion has gone up
slightly since the change, but this could also be due to chance.

Is there a statistical test I can use to give a probability to whether
I have made a beneficial change or not? Can anyone recommend me a good
book that covers the use of statistics in ecommerce or similar?

Thanks in advance,

Steve

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