Original: 7.7 new. 10.5 explain weather it decreased or it increased
2 answers:
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Answer:
Mean of the binomial distribution
μ = 174.972 bolts
Step-by-step explanation:
<u><em>Step(i):-</em></u>
Given that Bob tested 24 bolts that he randomly picked and found that 5 were defective
The proportion of the defective item
<u><em>Step(ii):-</em></u>
Let 'x' be a random variable in a binomial distribution
Mean of the binomial distribution
μ = np
μ = 840 ×0.280
μ = 174.972
<u><em>Final answer</em></u>:-
Mean of the binomial distribution μ = 174.972 bolts
Answer:
A sample of 139 should be taken.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
That is z with a pvalue of , so Z = 1.96.
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
Population standard deviation of $3,000.
This means that
How large a sample should be taken if the desired margin of error is $500?
A sample of n is needed.
n is found when M = 500. So
Dividing both sides by 500
Rounding up:
A sample of 139 should be taken.