A light bulb manufacturer claims that less than 5% of his bulbs are defective.When 1000 are drawn, only 1% are

Question

a) What is the population of interest?

b) What is the sample?

c) Does the 5% refer to the parameter or the statistic?

e) How can this statistic be used to make inferences about the parameter to test the claim?

I am really struggling with this, its only my first week of statistics, and I can't get past this question!

Answer 1

I believe the POPULATION is the total group from which a sample could be drawn.  In this case:  All the light bulbs produced by this manufacturer.

The SAMPLE is the 1000 light bulbs drawn out of the population.

Think of PARAMETERS as sort of boundaries or limits.  The manufacturer says, "We will have no more than 5% defects".  That's a limit... a boundary.  (6% would be outside the acceptable parameters.)

Yeah... making inferences:  All I can come up with is that the manufacturer may be  working too well:  If acceptable industry standards are a 5% failure rate - and if he is consistently so far below it he is, perhaps, over-manufacturing.  Or, he should launch an ad campaign heralding the exceptional quality of his product.