A manufacturer knows that the number of items produced per hour by machine A is normally distributed with a standard deviation of 9.4 items for machine A. The mean hourly amount produced by machine A for a random sample of 41 hours was 120 units. (a) Construct 95% confidence interval per hour by this machine. (b) What is the margin of error per hour? (c) How large a sample is needed if the desired margin of error is 0.2 for the confidence interval of 95%?
Added by Gregorio B.
Step 1
4 items), n is the sample size (41 hours), zα/2 is the critical value from the standard normal distribution corresponding to the desired level of confidence (95% or α = 0.05). From the standard normal distribution table, we find that zα/2 = 1.96. Substituting the Show more…
Show all steps
Close
Your feedback will help us improve your experience
Ana Carolina Da Cruz 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
A manufacturer knows that the number of items produced per hour by machine A is normally distributed with a standard deviation of 8.4 items for machine A. The mean hourly amount produced by machine A for a random sample of 40 hours was 130 units. (a) Construct 90% confidence interval per hour by this machine. (b) What is the margin of error per hour? (c) How large a sample is needed if the desired margin of error is 0.25 for the confidence interval of 90%?
Ahmet Y.
. A manufacturer knows that the numbers of items produced per hour by machine A and by machine B are normally distributed with a standard deviation of 8.4 items for machine A and a standard deviation of 11.3 items for machine B. The mean hourly amount produced by machine A for a random sample of 46 hours was 130 units; the mean hourly amount produced by machine B for a random sample of 40 hours was 120 units. Required: Find the 95% confidence interval for the difference in mean parts produced per hour by these two machines. Assume equal variance
Devanshu R.
A machine produces parts with lengths that are normally distributed with μ = 0.63. A sample of 9 parts has a mean length of 75.77. (a) Give a point estimate for μ. (Give your answer correct to two decimal places.) (b) Find the 99% confidence maximum error of estimate for μ. (Give your answer correct to three decimal places.) (c) Find the 99% confidence interval for μ.
Ana Carolina D.
Recommended Textbooks
Elementary Statistics a Step by Step Approach
The Practice of Statistics for AP
Introductory Statistics
Transcript
Watch the video solution with this free unlock.
EMAIL
PASSWORD