# Math Help - Confidence Intervals

1. ## Checking Confidence Intervals

An AP Statistics teacher asks her class to construct confidence intervals given a sample proportion of .45 and a variety of sample sizes. Four groups of students are each given a different sample size and the intervals from the groups are displayed on the chalkboard. Which of the following intervals must be incorrect? Explain how you made your decision.
Group A: (.37, .53)
Group B: (.41, .49)
Group C: (.35, .55)
Group D: (.40, .49)

All help is appreciated, thanks.

2. Here's a hint, the sample proportion must be in the middle of the constructed interval.

3. Sorry again.

The sample proportion is can be located in the middle of all of them, with the standard deviations possibly being .08, .04, .1, and .045.
The only one that seems out of the ordinary to me is D.

EDIT: Nevermind made a silly mistake.