ANSWER
• Inequality notation: 15 ≤ p ≤ 39
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• Interval notation: [15, 39]
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• Graph: ,see explanation section
Step-by-step explanation
If p is the percentage of teenagers who will have more than one episode of depression within two years, and this is between 15% and 39%, inclusive, it means that p is greater than or equal to 15 and less than or equal to 39. In inequality notation, 15 ≤ p ≤ 39.
Interval notation is the one where we use parenthesis () and/or brackets [] to express an interval. In this case, the interval is continuous between 15 and 39 and includes the two values, so we have to use brackets: [15, 39].
In a graph, we can draw a number line and highlight the line between 15 and 39, using filled circles to include those two values - sometimes brackets are used instead,