I am from a biology background. Using t, χ2, F tests day-to-day, following like a recipe. However, I feel I must understand the background of this.
I took an online lecture on p-value and hypothesis testing.
if your p-value is less than 0.01, then you have a very strong case against null hypothesis very strong case. The meaning of this is only in 1 % of the cases your null hypothesis will hold true in 99 % of the cases your null hypothesis will be false
Without many mathematical notations, could someone help me to understand;
1. why having a low probability is strong?
2. What p-value really tells in hypothesis testing? because some say it'd not about probability.
3. Is setting a null hypothesis a mathematical requirement?
4. Is normal distribution a hypothetical thing? because why we have to use different t, χ2, F distributions for different data types to calculate p-value.
I am not sure why I fail every time to understand this; is it mathematics or is it the language (wording) use to explain these concepts.