Answer:
a)
And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm
b)
Step-by-step explanation:
Part a
The confidence interval for the mean is given by the following formula:
(1)
In order to calculate the critical value
we need to find first the degrees of freedom, given by:
Since the Confidence is 0.95 or 95%, the value of
and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,51)".And we see that
Replacing we got:
And we can conclude that we are 95% confident that the true mean of Co2 level is between 608.29 and 700.03 ppm
Part b
The margin of error is given by :
(a)
The desired margin of error is ME =50/2=25 and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
The critical value for 95% of confidence interval now can be founded using the normal distribution. And in excel we can use this formla to find it:"=-NORM.INV(0.025;0;1)", and we got
, and we use an estimator of the population variance the value of 175 replacing into formula (b) we got:
The correct answer is A because when you solve everything in this equation, it comes out to 7=7=7=7=7, so this is correct. Just use your calculator to solve these.
Answer:
$72
Step-by-step explanation:
The sale offers 2 pair of shoes for $45, but the price is same for 1 pair of shoes.
The cost of 3 pair of shoes
= The sale price of 2 pair of shoes + Regular price of 1 pair of shoes
= $45 + $27
= $72
So, 3 pairs of shoes will cost $72 today.
It would be C since a scale factor of 2 makes the original A coordinate of (3,3) times 2 therefore the new coordinates being (6,6)