Answer:
Explanation:
From the question we are told that:
Null Hypothesis
Alternative Hypothesis

Sample size

standard deviation

Significance level

a)
Sample mean
Generally the equation for Test statistics is mathematically given by


Therefore from table

We conclude The value of test statistics is greater than critical value.
Therefore we Reject the Null hypothesis

b)
Sample mean
Generally the equation for Test statistics is mathematically given by


Therefore from table

We conclude,The value of test statistics is less than critical value.
Therefore we Fail to Reject the Null hypothesis

c)
Sample mean
Generally the equation for Test statistics is mathematically given by


Therefore from table

We conclude The value of test statistics is greater than critical value.
Therefore we Fail to Reject the Null hypothesis