Answered

Westonci.ca offers quick and accurate answers to your questions. Join our community and get the insights you need today. Experience the convenience of finding accurate answers to your questions from knowledgeable professionals on our platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Suppose that the lifetimes of a certain kind of light bulb are normally distributed with a standard deviation if 110 hours. If exactly 95% of the bulbs die before 920 hours, find the mean lifetime if the bulbs

Sagot :

Answer:

The mean life time of the bulbs is approximately 739 hours

Step-by-step explanation:

Here, we want to calculate the mean life time

From the question, 95% of the bulbs die before 920 hours

What this mean is that the probability that a bulb will die before 920 hours is 95% = 95/100 = 0.95

Now, we need the z-score that is exactly equal to this value

Using the standard normal distribution table, the z-score corresponding to this probability value is 1.645

Mathematically;

z-score = (x-mean)/SD

In this case, x is 920, SD is standard deviation which is 920 hours

thus, we have it that;

1.645 = (920-mean)/110

110(1.645) = 920 - mean

180.95 = 920 - mean

mean = 920- 180.95

mean = 739.05

Thank you for choosing our platform. We're dedicated to providing the best answers for all your questions. Visit us again. Thank you for your visit. We're committed to providing you with the best information available. Return anytime for more. Find reliable answers at Westonci.ca. Visit us again for the latest updates and expert advice.