Given the following hypotheses:
H0 : μ = 400
H1 : μ ≠ 400
A random sample of 12 observations is selected from a normal population. The sample mean was 407 and the sample standard deviation 6. Using the .01 significance level:
a.
State the decision rule. (Negative amount should be indicated by a minus sign. Round your answers to 3 decimal places.)
Reject H0 when the test statistic is (Click to select)insideoutside the interval (, ).
b. Compute the value of the test statistic. (Round your answer to 3 decimal places.)
Value of the test statistic
c. What is your decision regarding the null hypothesis?
Do not reject
Reject
So far I have t=xbar-mean/s squareroot6
Having trouble understanding how to find all of it, im so lost... :.(
a.
Decision rule: Reject null or 
if the test statistic is OUTSIDE the interval: - 3.106 to 3.106
b.
c.
With significance level (α) of .01, and degree of freedom of 11 (12 – 1), the t-critical values are: - 3.106 and 3.106.
The test statistic: 4.041 is greater than the right t-critical value: 3.106, and therefore falls in the reject region
Decision: Reject null or Reject : μ = 400.
There is sufficient evidence to warrant the rejection of the null hypothesis that: 
