A family has two cars. The first car has a fuel efficiency of 40 miles per gallon of gas and the second has a fuel efficiency of
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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
Ok so
for a thing that is P amount at first, with a half life of k days
after t days, the amount left is A
the equation is
given
13% of P remained=A
t=400
replace A with 0.13P and t with 400
0.13P=
divide both sides by P
take the ln of both sides
multiply both sides by k
divide oth sides by ln0.13
k=
evaluate
k=135.897 days
the half life is 135.897 days
for a thing that is P amount at first, with a half life of k days
after t days, the amount left is A
the equation is
given
13% of P remained=A
t=400
replace A with 0.13P and t with 400
0.13P=
divide both sides by P
take the ln of both sides
multiply both sides by k
divide oth sides by ln0.13
k=
evaluate
k=135.897 days
the half life is 135.897 days