Answer: The critical value of the test is 2.807.
Explanation:
Since we have given that
n = 24
So, the degree of freedom v = n-1 = 24 - 1=23
Since, n>30, so we will use 't-test'.
Here, α = 0.01
so, According to t-table, we get that

If we take α, then we are taking about two tail test.
If we take
then we are talking about one tail test.
But in both the cases, the result will be same.
Hence, the critical value of the test is 2.807.