X^2 -5x -20=0
(x - 5/2)^2 -20 -25/4=0
(x-5/2)^2-105/4=0
(x -5/2 -(105)^1/2)(x -5/2 +(105)^1/2)=0
factors are (x -5/2 -(105)^1/2) and
(x -5/2 -(105)^1/2)
Answer:
As the sample size increases, the variability decreases.
Step-by-step explanation:
Variability is the measure of actual entries from mean. The less the deviations the less would be the variance.
For a sample of size n, we have by central limit theorem the mean of sample follows a normal distribution for random samples of large size.
X bar will have std deviation as ![\frac{s}{\sqrt{n} }](https://tex.z-dn.net/?f=%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%20%7D)
where s is the square root of variance of sample
Thus we find the variability denoted by std deviation is inversely proportion of square root of sample size.
Hence as sample size increases, std error decreases.
As the sample size increases, the variability decreases.
Answer:
![y=-\frac{5}{2}x+\frac{3}{2}](https://tex.z-dn.net/?f=y%3D-%5Cfrac%7B5%7D%7B2%7Dx%2B%5Cfrac%7B3%7D%7B2%7D)
Step-by-step explanation:
![5x+2y=3\\\\2y=-5x+3\\\\y=-\frac{5}{2}x+\frac{3}{2}](https://tex.z-dn.net/?f=5x%2B2y%3D3%5C%5C%5C%5C2y%3D-5x%2B3%5C%5C%5C%5Cy%3D-%5Cfrac%7B5%7D%7B2%7Dx%2B%5Cfrac%7B3%7D%7B2%7D)
Answer:
Option D (r(t) = 3.50t +25
; r(8) = 53)
Step-by-step explanation:
The fixed cost to rent the kayak $25. This is the cost which remains fixed irrespective of the usage of the kayak. The variable cost of using the kayak is the cost which depends on the usage of the kayak. It is mentioned that the kayak is used for 4 hours and the company charges $3.5 for every half hour. The cost function is given by:
r(t) = 25 + 3.5t ; there r is the total cost of using the kayak and t is the number of half-hours the kayak is used.
4 hours means that there are 8 half-hours. Therefore, t=8. Put t=8 in r(t).
r(8) = 25 + 3.5*(8) = 25 + 28 = 53.
Therefore, Option D is the correct answer!!!
4
That’s what my tutor told me