Answer:
The 95% confidence interval of the mean annual contribution,
is
$529.21 <
< $570.79
Explanation:
The parameters given are;
The sample size, n = 50
The mean annual church contribution,
= $550
The standard deviation, σ = $75
The confidence level = 95%
The formula for finding the confidence interval having a known mean is given as follows;

Where, the z value at 95% confidence level = 1.96, we therefore have;

Which gives the 95% confidence interval of the mean annual contribution,
, as follows;
$529.21 <
< $570.79