Answer:
Step-by-step explanation:
Given that
n=28, ¯ x (x-bar)=50, and s=5
Here only sample std deviation is known, hence we can use only t critical value
df =n-1 =27
t critical = 2.05
Margin of error = [tex]2.05 *\frac{s}{\sqrt{n} } \\=1.937[/tex]
Confidence interval = 28±1.937
=(26.1, 29,9)