Question

In politics, marketing, etc. we often want to estimate a percentage or proportion p. One calculation in statistical polling is the margin of error - the largest (reasonble) error that the poll could have. For example, a poll result of 72% with a margin of error of 4% indicates that p is most likely to be between 68% and 76% (72% minus 4% to 72% plus 4%).

In a (made-up) poll, the proportion of people who like dark chocolate more than milk chocolate was 27% with a margin of error of 1.9%. Describe the conclusion about p using an absolute value inequality.



The answer field below uses the symbolic entry option in Mobius. That lets you type in a vertical bar | to represent absolute values. Also, when you type in and then =, the symbolic entry option will automatically convert that to ≥.



Be sure to use decimal numbers in your answer (such as using 0.40 for 40%).

Answer 1

|0.251 < p < 0.289|

Explanation:

Given that:

The proportion of people who like dark chocolate than milk chocolate in a made up poll is 27%

Margin of Error = 1.9%

The conclusion about the proportion p using absolute value inequality ;

Interval :

P ± margin of error

27% ± 1.9%

(27 - 1.9)% ; (27 + 1.9)%

25.1% ; 28.9%

0.251 ; 0.289

Hence,

|0.251 < p < 0.289|