Could really understand the question

Standard deviation, mean, variance, z-scores, t-tests, etc.
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zorro
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Could really understand the question

Postby zorro » Fri Jul 02, 2010 2:29 am

Question :

A random sample of 500 components was taken from a large consignment and 60 were found to be defective . Obtain the 98% confidence limits for the percentage of defective components in the consignment
(Note that significant value of Z at 2% level of significance is 2.33)

please just point me to the right direction

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Martingale
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Re: Could really understand the question

Postby Martingale » Fri Jul 02, 2010 2:58 am

zorro wrote:Question :

A random sample of 500 components was taken from a large consignment and 60 were found to be defective . Obtain the 98% confidence limits for the percentage of defective components in the consignment
(Note that significant value of Z at 2% level of significance is 2.33)

please just point me to the right direction


Where are you stuck?

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zorro
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Re: Could really understand the question

Postby zorro » Sat Jul 03, 2010 6:10 am

How do i know what is the standard deviation in this problem

from the question i can figure out that

n = 500
= 60

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Re: Could really understand the question

Postby Martingale » Sat Jul 03, 2010 2:34 pm

zorro wrote:How do i know what is the standard deviation in this problem

from the question i can figure out that

n = 500
= 60


you need to use



Where

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Re: Could really understand the question

Postby zorro » Sat Jul 03, 2010 6:36 pm

Martingale wrote:you need to use



Where


Could u please tell what is the name of the formula ?? :confused:

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Re: Could really understand the question

Postby Martingale » Sat Jul 03, 2010 8:08 pm

zorro wrote:Could u please tell what is the name of the formula ?? :confused:


It's the confidence interval for population proportions (assuming normality)

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Re: Could really understand the question

Postby zorro » Sun Jul 04, 2010 5:40 am

Thanks All :mrgreen: :clap:


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