Answer:
a
The 90% confidence interval is
b
Confidence interval for the population men between <u>$52561.13</u> up to <u>$57540.8</u>
Step-by-step explanation:
From the question we are told that
The sample size is
The sample mean is
The standard deviation is
Given that the confidence level is 90% then the level of confidence is mathematically represented as
Next we obtain the critical value of from the normal distribution table the values is
Generally the margin of error is mathematically represented as
substituting values
The 90% confidence interval is mathematically evaluated as
substituting values