I need help with D only. Finding the probability of selecting someone between 20 and 34 years old.
2 answers:
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Answer:
The 95 percent confidence interval for the true mean metal thickness is between 0.2903 mm and 0.2907 mm
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 .
So it is z with a pvalue of , so
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.
The lower end of the interval is the sample mean subtracted by M. So it is 0.2905 - 0.0002 = 0.2903 mm
The upper end of the interval is the sample mean added to M. So it is 0.2905 + 0.0002 = 0.2907 mm
The 95 percent confidence interval for the true mean metal thickness is between 0.2903 mm and 0.2907 mm
Step-by-step explanation:
The given numbers are : 32 , 48 , 140 , 120
First number is 32
Second number is 48
Third number is 140
Fourth number is 120
First number/second number :
Third number/Fouth number :
From equation (1) and (2) we can see that the ratio is not same. Hence, they are not in proportion.