S is slope
S= rise/run
S1=3/12=1/4
S2=2/16=1/8
S3=5/15=1/3
S4=4/20=1/5
Deepest slope S3 aka C
Answer:
We have been given a unit circle which is cut at k different points to produce k different arcs. Now we can see firstly that the sum of lengths of all k arks is equal to the circumference:

Now consider the largest arc to have length \small l . And we represent all the other arcs to be some constant times this length.
we get :

where C(i) is a constant coefficient obviously between 0 and 1.

All that I want to say by using this step is that after we choose the largest length (or any length for that matter) the other fractions appear according to the above summation constraint. [This step may even be avoided depending on how much precaution you wanna take when deriving a relation.]
So since there is no bias, and \small l may come out to be any value from [0 , 2π] with equal probability, the expected value is then defined as just the average value of all the samples.
We already know the sum so it is easy to compute the average :

Answer:
Step-by-step explanation:
Given that in order to efficiently bid on a contract, a contractor wants to be 95% confident that his error is less than two hours in estimating the average time it takes to install tile flooring.
Std deviation =4.5 errors
95% confidence interval = Mean±1.96*std dev
Hence we have

Sample size should be 20.
Answer:
For this distribution of test scores, the standard deviation is equal to the square root of 9
D) 9
Step-by-step explanation:
We need to know the standard deviation formula:
(1)
Where:
S: Standard deviation
sum: Summation
x: Sample values
Am: Arithmetic mean
n:
Number of terms, in this case 3
Now, we need to know the arithmetic mean of the sample values: 2, 5 and 8

To know the standard deviation we need to have the summation of each term minus the arithmetic mean squared.
of each term:

Now, we can find the standard deviation:

The standard deviation is equal to the square root of 9