Question

Population proportion of defective pieces?

http://s304.photobucket.com/user/tyronneguillory57/media/it_zpsyfezh1e1.png.html?sort=3&o=0

I want to go with 100 pieces defective but different samples could have a different number of defective flags. @amistre64

Answer 1

I get 100 defective because 2000/40=50 and 50 times 2(number of defective in sample)=100

Answer 2

anyting less then 26 is defective ... i see only 2 of the sample of 40 that qualify. both of them are 25.

but the queston is: does the estimator mean that the population itself MUST be the same as the sample? or does one sample vary from another?

Answer 3

Each sample would vary.

Answer 4

yes 2 defective in that sample of 40 but if you calculate up to 2000 that would be 100 defective. But each sample could be different.

Answer 5

since this is only one of many possible samples; then we cannot that it is equal to the population. we can assume that this sample is one of many ... and that all the samples are normally distributed about the populations true parameter.

using a 5% unusual rule. we would expect this one sample to be within 95% of the true population parameter. so we would spread out an interval and say that the true population parameter is expected to be within that interval.

no interval is given and we cannot say with certitude that the sample is exact to th epopulation.

Answer 6

2/40 +- 1.96(2(38)/40^3)

gives us the interval in which we are 95% confident that the true population porportion is bounded by

Answer 7

2000(0.0476725) to 2000(0.0523275)

96 to 105 is the range of expected defects in the population

Answer 8

So more than 100 pieces must be defective?

Answer 9

is that what you got from that?

Answer 10

yes

Answer 11

say my grandma is between 96 and 105 years old

can we say she must be 5?
can we say she must be 100?
can we say for certain that she must be over 100?
can we say that she must be equal to 2/40?
or should we simply conclude that we need more information ....

Answer 12

We would need more information.

Answer 13

then lets stick to saying we simply need more information for this problem ...

Answer 14

So for this question the data would be insufficient.

Answer 15

thats what my money is on yes :)