You estimate the model Y=0 + 1X1+ 2X2 + using a sample of more than 1000 observations. X1 is the main intervention variable. X2 is a control variable. You get the following results:

The estimated value, = 4.80

The corresponding Standard Error of = 2.40

(You do not need to worry about 0 for this question).

A: What is the null hypothesis that we are testing regarding 1? (1 point)

B: Based on the above, please calculate the following for the estimated 1 :

1. a) The t-statistic.
2. b) The 95% confidence interval.
3. c) The 99% confidence interval.
4. d) Would the corresponding p-value be greater than 0.05 or less than 0.05? Would it be greater than 0.01 or less than 0.01?
5. f) If you can reject the null with 95% confidence, does it automatically mean you can reject it with 99% confidence? What about the opposite case - if you reject a null with 99% confidence, does it automatically mean you can reject it with 95% confidence? Explain very briefly.