[University Statistics] 5% Hypothesis testing

Hi everyone! I was hoping someone could help me tackle this problem, I'm struggling to get this concept and was hoping someone could clear it up for me. Here is one of the questions, if I can understand this one, I should be able to complete the remainder of the assignment.

The Espresso Company makes vending machines that are supposed to supply on average 4 oz. of espresso into a cup, and you think it is not giving you enough. You decide to do a scientific test to see if this is true. Over the next few weeks, you take a random sample of 45 cups of espresso from the machine: the sample’s mean is 3.8 oz. and the standard deviation is .3 oz. Use a 5% level of significance and the appropriate hypothesis test to see if there is enough evidence that the vending machine is depriving you the amount you purchased.

A) What are the null and alternate hypotheses?

P = 4

P =! (does not equal) 4

B) What is the test statistic?

I’m not sure how to get this number?

C) What is the P- Value

Again not sure how to get this number

D) Do you reject or fail to reject the null hypothesis?

How would I determine that?