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:
Answer:
52 - 48 = 4
Around 7%
(Please tell me if this is wrong)
Answer:
i
Step-by-step explanation:
Step-by-step explanation:
(note: I'm only answering the ones I know vs giving you wrong answers for the others!)
1. ROS=Obtuse (larger then ninty degrees)
2. octagon has 8 angles (octo means eight, after all!)
3. If a figure has three sides, it is a triagle (not positive on this one)
4. symmetric property of congruence (this one's a simple search :p )
5. N/A (although I believe its angle BEC=124 degrees, as every other choice Is proven to be true)
6. congruent complements theorem (this is because we are given that 3 is a suppliment of 4. we are also given that 2=4. Based on this, then 1=3 is congruent based on 1 being suppliment of 2, 2=4, and 3 being a suppliment of 4)
7. N/A
8. N/A (the picture is too fuzzy for me to make any ideas)
I'm sorry I couldn't solve them all, but I hope this at least gets you somewhere! Have a great day!
<span>D. One hundred random students from the sixth grade is the best choice given!
</span><span>
Reasons why the other answers and not good choices.
A. The first 100 students from an alphabetical list of the entire school, is incorrect because his only concern is the 6th graders, by including everyone he would negatively skew the data.
B. The first 100 students from an alphabetical list of sixth graders, is incorrect because its unfair to those with names starting later in the alphabet.
C. One hundred random students from the entire school </span>is is better but still incorrect because his only concern is the 6th graders, <span>by including everyone he would again negatively skew the data.</span>
