Answer:
The value of the test statistic is 
Step-by-step explanation:
The null hypothesis is:

The alternate hypotesis is:

Our test statistic is:

In which X is the sample mean,
is the null hypothesis value,
is the standard deviation and n is the size of the sample.
In this problem:

So



The value of the test statistic is 
Answer:
gdfgdf
Step-by-step explanation:
Answer:
4.2 or 4
Step-by-step explanation:
√18 = 4.24264068712
or 4.2
or 4