Answer:
The 90% confidence level is
Step-by-step explanation:
From the question we are told that
The sample size is
The mean age is
The standard deviation is
Generally the degree of freedom for this data set is mathematically represented as
substituting values
Given that the level of confidence is 90% the significance level is mathematically evaluated as
10 %
Now
Since we are considering a on tail experiment
The critical value for half of this significance level at the calculated degree of freedom is obtained from the critical value table as
The margin for error is mathematically represented as
substituting values
he 90% confidence interval for the true average age of all students in the university is evaluated as follows
substituting values