Answer:
The margin of error for a 90% confidence interval is 0.075.
Step-by-step explanation:
We are given that he asks listeners to phone in and vote "yes" if they agree the drinking age should be lowered and "no" if not.
Of the 100 people who phoned in, 70 answered "yes."
Let = sample proportion of people who say yes
So, =
= 0.70
where, X = Number of people who say yes = 70
n = Number of people phoned in = 100
<u>Now, Margin of error formula for any confidence interval is given by;</u>
Margin of error =
where, = level of significance = 10%
Standard of error =
Also, the critical value of x at 5% () level of significance is 1.645.
SO,<em><u> Margin of Error</u></em> =
=
= 0.075
Hence, the margin of error for a 90% confidence interval is 0.075.