Answer:
At least 68% of observations lie between 22 and 26 months.
Step-by-step explanation:
The Empirical Rule states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 24
Standard deviation = 2
22 = 24 - 2
22 is one standard deviation below the mean
26 = 24 + 2
26 is one standard deviation above the mean.
So, by the empirical rule, at least 68% of observations lie between 22 and 26 months.
