Based on a random sample of 170 married couples in Britain, a researcher finds that the relationship between the husbands’ and wives’ ages is described by the following equation:

Which of the following is the **best** interpretation of the slope estimate?

- For each additional year increase of wife’s age, we would expect the husband’s age to be 0.91 years higher, on average.
- On average, when a husband in Britain gets 1 year older, his wife only gets 0.91 years older.
- For each additional year increase of husband’s age, we would expect the wife’s age to be 0.91 years higher, on average.
- Most wives in Britain are 0.91 years younger than their husbands.