100 POINTS! ANSWER NOW! I'm really slow so please explain this as thoroughly as possible.
1 answer:
Step-by-step explanation:
a) The graph of a normal curve with a mean of 64" and a standard deviation of 3.5" is a bell-shaped curve with its
maximum value at x = 64.
Important points:
mean - 3 deviations: 64 - 3(3.5) = 64 - 10.5 = 53.5
mean - 2 deviations: 64 - 2(3.5) = 64 - 7 = 57
mean - 1 deviation: 64 - 3.5 = 60.5
mean: = 64
mean + 1 deviation: 64 + 3.5 = 67.5
mean + 2 deviations: 64 + 2(3.5) = 64 + 7 = 71
mean + 3 deviations: 64 + 3(3.5) = 64 + 10.5 = 74.5
b) If there are 3000 plants, approximately how many will be taller than 71"?
71" is 2 standard deviations above the mean. The region between two standard deviations below the mean and two standard deviations holds approximately 95% of the plants.
Therefore there will be approximately 5% of the plants divided equally between being taller than two standard
deviations above the mean and being shorter than two standard deviations below the mean. Thus, there will be
approximately 2.5% of the plants taller than 71": 0.025 x 3000 = 75 plants.
or
the z-score for 71
= (71-64)/35 = 2
going to your tables, or some other suitable source for standard deviation, we find
P(z < 2) = .9772
P(z > 2) = .0228
.0228(3000) = 68.4
or appr 68 plants
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Hi there,
Your question is "twice a number (x) is fifty"
Recall how a number is represented by x.
Twice a number would be represented as 2x.
Therefore, to represent that twice a number is equal to 50, that would result in the expression:
If you're looking to solve this equation, it's often best to think about the "reverse" of the current equation.
Notice how 2 is multiplying the x.
To isolate x, divide that side by 2.
However, recall that whatever is done to one side of an equation must also be done to the other side of the equation. Therefore, you will need to divide both sides by 2.
Equation:
Solving for x: 25
Hope that helps!