Answer: the probability of a bulb lasting for at most 552 hours is 0.953.
Step-by-step explanation:
Since the life of light bulbs are distributed normally, we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = the life of light bulbs in hours.
µ = mean hour
σ = standard deviation
From the information given,
µ = 510 hours
σ = 25 hours
We want to find the probability of a bulb lasting for at most 552 hours. It is expressed as
P(x ≤ 552)
For x = 552
z = (552 - 510)/25 = 1.68
Looking at the normal distribution table, the probability corresponding to the z score is 0.953
