The equation to use here is 3^x = 81. You could start to try numbers, and you would realize that x = 4 weeks.
Answer:
The sample standard deviation is 393.99
Step-by-step explanation:
The standard deviation of a sample can be calculated using the following formula:
![s=\sqrt[ ]{\frac{1}{N-1} \sum_{i=1}^{N}(x_{i}-{\displaystyle \textstyle {\bar {x}}}) ^{2} }](https://tex.z-dn.net/?f=s%3D%5Csqrt%5B%20%5D%7B%5Cfrac%7B1%7D%7BN-1%7D%20%5Csum_%7Bi%3D1%7D%5E%7BN%7D%28x_%7Bi%7D-%7B%5Cdisplaystyle%20%5Ctextstyle%20%7B%5Cbar%20%7Bx%7D%7D%7D%29%20%5E%7B2%7D%20%7D)
Where:
Sample standart deviation
Number of observations in the sample
Mean value of the sample
and
simbolizes the addition of the square of the difference between each observation and the mean value of the sample.
Let's start calculating the mean value:




Now, let's calculate the summation:


So, now we can calculate the standart deviation:
![s=\sqrt[ ]{\frac{1}{N-1} \sum_{i=1}^{N}(x_{i}-{\displaystyle \textstyle {\bar {x}}}) ^{2} }](https://tex.z-dn.net/?f=s%3D%5Csqrt%5B%20%5D%7B%5Cfrac%7B1%7D%7BN-1%7D%20%5Csum_%7Bi%3D1%7D%5E%7BN%7D%28x_%7Bi%7D-%7B%5Cdisplaystyle%20%5Ctextstyle%20%7B%5Cbar%20%7Bx%7D%7D%7D%29%20%5E%7B2%7D%20%7D)
![s=\sqrt[ ]{\frac{1}{15-1}*(2173160)}](https://tex.z-dn.net/?f=s%3D%5Csqrt%5B%20%5D%7B%5Cfrac%7B1%7D%7B15-1%7D%2A%282173160%29%7D)
![s=\sqrt[ ]{\frac{2173160}{14}}](https://tex.z-dn.net/?f=s%3D%5Csqrt%5B%20%5D%7B%5Cfrac%7B2173160%7D%7B14%7D%7D)

The sample standard deviation is 393.99
Given:
Length of chords of one segment = 11 and 8
Length of chords of other segment = 2 and x
To find:
The value of x.
Solution:
<em>If two chords intersect each other inside a circle, the products of length their segments are equal.</em>



Divide by 2 on both sides.


Switch the sides.

The value of x is 44.
There is no solution because the lines do not intersect