statsboy69
New member
- Joined
- Nov 7, 2011
- Messages
- 1
here's the problem, I do not understand how to solve this problem using confidence interval, or whatever is needed
quality-control monitoring procedures are almost always statistical. often, to check the
quality of a product requires that it be used up or even destroyed, so it's never
possible to do a quality check on every product. an agent must select a sample.
in the case of a product like latex surgical gloves, "quality" is related to consistent latex
thickness, and the relationship can be complex. for instance, a glove that is a little too
thick might slightly reduce the sensitivity of a surgeon's fingers, which could possibly
lead to the surgeon overlooking a clinical fact because he or she couldn't feel it
through the glove. this condition is obviously undesirable, so it's important that gloves
not be too thick. on the other hand (bad pun, sorry), a glove that's too thin might
break, bringing the risk of infection to surgeon and patient alike. this condition is close
to a disaster (much worse than simply undesirable), so it's absolutely imperative that
gloves not be too thin.
imagine a manufacturer of surgical gloves with latex thickness known to be
approximately normally distributed with mean thickness 244 microns (μm) and
standard deviation 13μm. according to the manufacturer's quality-control procedures,
latex in the 95th percentile or higher is defined to be "too thick," capable of reducing
sensation in a surgeon's fingertips. at the other extreme, latex thickness below 200μm
is defined to be "too thin," putting the glove at risk of breakage.
to monitor latex thickness in its product, a quality control agent selects a random
sample of 30 gloves from each production run. if none are found to be at risk of
breakage (zero tolerance for gloves that are too thin), and no more than three exceed
the maximum thickness standard, the agent will certify the quality of the entire
production run.
1. what's the maximum thickness allowed by the manufacturer's standard?
2. is there any reasonable chance that the average thickness of the gloves in the
agent's sample will exceed the maximum thickness allowed? why or why not?
3. what's the probability that a randomly selected glove
a) exceeds the maximum thickness standard?
b) is at risk of breakage?
c) meets both thickness standards?
4. what's the probability that a production run will fail the quality certification test?
any help would be great
quality-control monitoring procedures are almost always statistical. often, to check the
quality of a product requires that it be used up or even destroyed, so it's never
possible to do a quality check on every product. an agent must select a sample.
in the case of a product like latex surgical gloves, "quality" is related to consistent latex
thickness, and the relationship can be complex. for instance, a glove that is a little too
thick might slightly reduce the sensitivity of a surgeon's fingers, which could possibly
lead to the surgeon overlooking a clinical fact because he or she couldn't feel it
through the glove. this condition is obviously undesirable, so it's important that gloves
not be too thick. on the other hand (bad pun, sorry), a glove that's too thin might
break, bringing the risk of infection to surgeon and patient alike. this condition is close
to a disaster (much worse than simply undesirable), so it's absolutely imperative that
gloves not be too thin.
imagine a manufacturer of surgical gloves with latex thickness known to be
approximately normally distributed with mean thickness 244 microns (μm) and
standard deviation 13μm. according to the manufacturer's quality-control procedures,
latex in the 95th percentile or higher is defined to be "too thick," capable of reducing
sensation in a surgeon's fingertips. at the other extreme, latex thickness below 200μm
is defined to be "too thin," putting the glove at risk of breakage.
to monitor latex thickness in its product, a quality control agent selects a random
sample of 30 gloves from each production run. if none are found to be at risk of
breakage (zero tolerance for gloves that are too thin), and no more than three exceed
the maximum thickness standard, the agent will certify the quality of the entire
production run.
1. what's the maximum thickness allowed by the manufacturer's standard?
2. is there any reasonable chance that the average thickness of the gloves in the
agent's sample will exceed the maximum thickness allowed? why or why not?
3. what's the probability that a randomly selected glove
a) exceeds the maximum thickness standard?
b) is at risk of breakage?
c) meets both thickness standards?
4. what's the probability that a production run will fail the quality certification test?
any help would be great