1 answer:
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Answer:
Step-by-step explanation:
given that certain tubes manufactured by a company have a mean lifetime of 800 hours and a standard deviation of 60 hours.
Sample size n =16
Std error of sample mean =
x bar follows N(800, 15)
the probability that a random sample of 16 tubes taken from the group will have a mean lifetime
(a) between 790 and 810 hours,
=
(b) less than 785 hours
, (c) more than 820 hours,
(d) between 770 and 830 hours
=
Answer:
the standard error of the proportion is 0.0272
Step-by-step explanation:
We have that if the sample size is greater than 5% of the entire population, a finite population correction factor (fpc) is multiplied with the standard error :
fpc =
We know that N = 250 n = 91, replacing:
fpc =
fpc = 0.799
Now, the formula would then be:
SE = *fpc
Now replacing, knowing that p = 0.12
SE= *0.799
SE = 0.0272
So the standard error of the proportion is 0.0272