These are the only numbers you can multiply to get to 18.
1x18
2x9
3x6
18x1
9x2
6x3
Answer: 
Step-by-step explanation:
Given : Sample size : n= 9
Degree of freedom = df =n-1 =8
Sample mean : 
sample standard deviation : 
Significance level ; 
Since population standard deviation is not given , so we use t- test.
Using t-distribution table , we have
Critical value = 
Confidence interval for the population mean :
90% confidence interval for the mean value will be :
Hence, the 90% confidence interval for the mean value=
The fence is 210 ft long.
There is a post every 3.5 ft.
If you divide 210 ft by 3.5 ft, you get the number of spaces between posts.
(210 ft)/(3.5 ft) = 60
The fence starts with a post. Then there is 3.5 ft of fencing. Then there is another post. Then there is another 3.5 ft of fencing followed by a post. In total there are 61 posts.
Here's another way of thinking of why you end up with 60 posts.
For each 3.5 ft of fencing, you place a post at the end of the fencing.
Since there are 60 3.5-ft-long pieces of fencing, there will be 60 posts, one at the end of each piece of fencing. The first thing that is done is to put the initial post before any fencing is put up. The first post plus 60 more posts add up to 61 posts.
Now that you see why there are 61 posts, we can calculate their cost.
61 * $8.50 = $518.50
Using it's formula, it is found that the mean of the discrete random variable is given by:
B. 30.47.
<h3>What is the mean of a discrete distribution?</h3>
The expected value of a discrete distribution is given by the <u>sum of each outcome multiplied by it's respective probability</u>.
Hence, considering the table, the mean of the discrete distribution is:
E(X) = 23 x 0.16 + 25 x 0.09 + 26 x 0.18 + 31 x 0.12 + 34 x 0.24 + 38 x 0.21 = 30.47.
Hence option B is correct.
More can be learned about the mean of a discrete random variable at brainly.com/question/26660401
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