Question

let a represent the battery life of a brand a laptop, and let b represent the battery life of a brand b laptop. the mean difference in battery life between these two brands of laptops, d = a - b, is -3.25 hours. what is the correct interpretation of this value?
on average, brand b gains 3.25 hours of battery life daily.
on average, brand a loses 3.25 hours of battery life daily.
both brands are typically losing 3.25 hours of battery life daily.
on average, brand bs battery life lasts 3.25 hours longer than brand a.

Explanation:

Given \(D = A - B=- 3.25\), we can rewrite it as \(A=B - 3.25\). This means that on average, the battery life of brand \(A\) (\(A\)) is \(3.25\) hours less than the battery life of brand \(B\) (\(B\)). In other words, brand \(B\)'s battery life lasts \(3.25\) hours longer than brand \(A\).

Answer:

On average, brand B's battery life lasts 3.25 hours longer than brand A.