675 people will have score between 85 and 120
Step-by-step explanation:
Given
Mean = 100
SD = 15
If we have to find percentage of score between two values we have to find the z-score for both values and then area under the curve for both values
z-score is given by:
for a value x:
So,
For 85:
Now we have to find the area under the curve for both values of z-score. z-score tables are used for this purpose.
So,
For z1 : 0.1587
For z2: 0.9082
The area between z11 and z2:
So the probability of score between 85 and 120 is 0.7495
As the sample is of 900 people, the people with scores between 85 and 120 will be:
900*0.7495 = 674.55 people
Rounding off to nearest whole number
675 people will have score between 85 and 120
Keywords: Probability, SD
Learn more about probability at:
#LearnwithBrainly
Answer:
b
Step-by-step explanation:
The answer to your problem is
x=5/2
y=5
x=-4
y=2
Answer: choice D) 20
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Explanation:
Locate 3 on the x axis number line. Draw a vertical line through 3 and this vertical line will cross the parabola at some point P. Mark this point P on the parabola. Then draw a horizontal line from P to the y axis. The horizontal line will land on y = 10. In short, this all shows us that (3,10) is a point on this parabola.
Repeat those steps above, but now for x = 7. You'll see that (7,90) is another point on this parabola.
We need to find the slope of the line through the two points (3,10) and (7,90). The average rate of change from x = 3 to x = 7 is the same as the slope of the line through those two points.
To find the slope, we use the slope formula
m = (y2 - y1)/(x2 - x1)
where (x1,y1) and (x2,y2) are the two points, and m is the slope
In this case,
(x1,y1) = (3,10) and (x2,y2) = (7,90)
further breaking down to
x1=3
y1=10
x2=7
y2=90
So we'll plug those four pieces of info into the equation and simplifying to get...
m = (y2 - y1)/(x2 - x1)
m = (90 - 10)/(7 - 3)
m = 80/4
m = 20
The slope of the line is 20, so therefore, the average rate of change is 20.
