Using the Empirical Rule, it is found that the lifespans, in months, are given by:
1. 24 and 32.
2. 20 and 36.
3. 16 and 40.
It states that, for a normally distributed random variable:
Hence, considering the mean of 28 months and the standard deviation of 4 months, the life spans are given by:
1. 24 and 32.
2. 20 and 36.
3. 16 and 40.
More can be learned about the Empirical Rule at https://brainly.com/question/24537145