Answer:
Usual, because the result is between the minimum and maximum usual values.
Step-by-step explanation:
To identify if the value is usual or unusual we're going to use the Range rule of thumbs which states that most values should lie within 2 standard deviations of the mean. If the value lies outside those limits, we can tell that it's an unusual value.
Therefore:
Maximum usual value: μ + 2σ
Minimum usual value: μ - 2σ
In this case:
μ = 153.1
σ = 18.2
Therefore:
Maximum usual value: 189.5
Minimum usual value: 116.7
Therefore, the value of 187 lies within the limits. Therefore, the correct option is D. Usual, because the result is between the minimum and maximum usual values.
Answer:
No.
Step-by-step explanation:
It is not because 20 is not a perfect square.
Answer:
a = - 4, b = 5
Step-by-step explanation:
Expand the left side and compare the coefficients of like terms on the right side.
- 3(2x² + ax + b)
= - 6x² - 3ax - 3b
Comparing like terms with - 6x² + 12x - 15
x - term → - 3a = 12 ( divide both sides by - 3 )
a = - 4
constant term → - 3b = - 15 ( divide both sides by - 3 )
b = 5
