The lifetime of a certain brand of light bulbs is known to be normally distributed. A sample of 15 bulbs gives a mean lifetime of 138.0 hours with a standard deviation of 5.0 hours. Use Excel to calculate the upper limit of a 90% confidence interval for the mean lifetime of light bulbs of this brand.
Added by Francisco Jose E.
Step 1
We have a sample of 15 light bulbs with a mean lifetime of 138.0 hours and a standard deviation of 5.0 hours. Show more…
Show all steps
Close
Your feedback will help us improve your experience
Hoan Nguyen and 86 other Intro Stats / AP Statistics educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
The lifetime of a certain brand of electric light bulb is known to have a standard deviation of 45 hours. Suppose that a random sample of 70 bulbs of this brand has a mean lifetime of 481 hours. Find a 90% confidence interval for the true mean lifetime of all light bulbs of this brand. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: Upper limit:
Ana Carolina D.
The lifetime of a certain brand of electric light bulb is known to have a standard deviation of 46 hours. Suppose that a random sample of 90 bulbs of this brand has a mean lifetime of 493 hours. Find a 95% confidence interval for the true mean lifetime of all light bulbs of this brand. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: Upper limit:
Hoan N.
The lifetime of a certain brand of electric light bulb is known to have a standard deviation of 52 hours. Suppose that a random sample of 80 bulbs of this brand has a mean lifetime of 478 hours. Find a 90% confidence interval for the true mean lifetime of all light bulbs of this brand. Then give its lower limit and upper limit. Carry your intermediate computations to at least three decimal places. Round your answers to one decimal place. (If necessary, consult a list of formulas.) Lower limit: Upper limit:
Qudsiya A.
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD