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:
4
Is 4/10 which can be simplified to 2/5
Answer:
the schedule and the algebraic expression
The ratio of length to width is 3/2. Let's set up equations of ratios using first the 25 cm length of the paper and then the 20 cm width:
3 25 cm
--- = ----------
2 x
Solving for x, 3x = 50 cm, and x =16 2/3 cm. This is possible, since 16 2/3 is less than the paper width 20 cm.
3 20 cm
--- = -----------
2 x
Solving for x: 3x = 40 cm; x = 40/3 cm, or x= 13 1/3 cm. This is possible, but does not make maximum use of the 20 by 30 cm paper.
Answer: the largest flag Jake can draw on the paper given is 20 cm (length) by 16 2/3 cm.
Answer:
y=3-3/4x
Step-by-step explanation:
3x+4y=12
-3x -3x
4y=12-3x
/4 /4
y=3-3/4x
