Answer:
(a)Mean=9
(b)Median=9.5
(c)Mode=12
(d)Standard Deviation=2.53
Step-by-step explanation:
The sample of the number of vehicles that proceeded through the intersection after the light changed for 6 days during a 1 month period is given below:
6 12 7 12 8 9
(a)Mean
![Mean=\frac{6+12+ 7+ 12+ 8+ 9}{6} \\=\frac{54}{6} \\Mean=9](https://tex.z-dn.net/?f=Mean%3D%5Cfrac%7B6%2B12%2B%207%2B%2012%2B%208%2B%209%7D%7B6%7D%20%5C%5C%3D%5Cfrac%7B54%7D%7B6%7D%20%5C%5CMean%3D9)
(b)Median
First, arrange in ascending order
6,7,8,9,12,12
Since we have two terms in the middle, we take the average.
![Median=\frac{8+9}{2}\\Median=8.5](https://tex.z-dn.net/?f=Median%3D%5Cfrac%7B8%2B9%7D%7B2%7D%5C%5CMedian%3D8.5)
(c)Mode
The mode is the number with the highest frequency. The mode number of cars is 12.
(d)Standard Deviation
![S.D.=\sqrt{\dfrac{\sum_{i=1}^{n}(x-\bar{x})^2}{n-1}}](https://tex.z-dn.net/?f=S.D.%3D%5Csqrt%7B%5Cdfrac%7B%5Csum_%7Bi%3D1%7D%5E%7Bn%7D%28x-%5Cbar%7Bx%7D%29%5E2%7D%7Bn-1%7D%7D)
![S.D.=\sqrt\frac{(6-9)^2+(7-9)^2+(8-9)^2+(9-9)^2+(12-9)^2+(12-9)^2}{6-1}](https://tex.z-dn.net/?f=S.D.%3D%5Csqrt%5Cfrac%7B%286-9%29%5E2%2B%287-9%29%5E2%2B%288-9%29%5E2%2B%289-9%29%5E2%2B%2812-9%29%5E2%2B%2812-9%29%5E2%7D%7B6-1%7D)
![=\sqrt{6.4} \\S.D.=2.53](https://tex.z-dn.net/?f=%3D%5Csqrt%7B6.4%7D%20%5C%5CS.D.%3D2.53)
Answer:
I think so, but don't lose sight
Y2-y1
-------- = slope = 1
x2-x1
Point slope formula:
y-3=1(x-0)
y=x+3.... just plug the X values in and see if they equal the Y values
She makes 20 observations in all, because there are 5 groups with 4 students in each group. 5x4=20