Answer:
Mean = 14.5 years and standard deviation = 0.34 years
Explanation:
Data provided in the question:
Mean of the normal distribution = 14.5 years
Population standard deviation, σ = 2.5 years
Sample size = 55 students
Now,
The mean of the sample of 55 students will remain the same i.e 14.5 years
and,
Standard deviation of the sample of 55 students will be calculated using the formula
=

here n is the sample size
thus,
Standard deviation of the sample of 55 students, σₓ =

= 0.337 ≈ 0.34
Hence,
the Mean = 14.5 years and standard deviation = 0.34 years