Term
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Definition
| values of two different variables that are obtained from the same population element. |
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| BIVARIATE--2 qualitative variables |
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Definition
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| BIVARIATE-- 1 Qualitative, 1 Quantitative |
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Definition
| displayed side-by-side as separate samples to compare |
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| BIVARIATE-- 2 Quanitative |
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Definition
| displayed as ordered pairs(x,y) x=input (independent); y=output (dependent) |
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Definition
| plot of all ordered pairs of bivariate data on coordinate axis (x=horizontal, y=vertical) |
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Definition
| measures strength of linear relationship between two variables. |
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Definition
| as x increases, there is no shift in y values |
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Definition
| y increases as x increases |
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Definition
| y decreases as x increases |
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Term
| coefficient of linear correlation |
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Definition
| numerical measure of strength of the linear relationship between two variables. (reflects consistency of the effect that a change has on the other) |
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| Coefficient of Linear Correlation (Standards) |
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Definition
---r, between -1 (negative correlation) and +1 (positive correlation).
---closer r is to 0, less correlated |
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Term
| Pearson's Product Moment Definition Formula |
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Definition
Definition: R=[Σ(x-xbar)(y-ybar)]/[(n-1)sxsy]
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Term
| Pearson's Product Moment Computational Formula |
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Definition
Sum of Squares for xy divided by the squae root of the sum of squares for x multiplied by the sum of squares for y
R = SS(xy)/√SS(x)SS(y)
- SS(x)= Σx^2-((Σx)^2/n)
- SS(y)= Σy^2-((Σy)^2/n)
- SS(xy)= Σxy-((ΣxΣy)/n)
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Term
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Definition
variable that is not included in a study but has an effect on the variables of the study and makes it appear that those variables are related.
ex) relationship shown between the amount of damage caused by a fire and the number of firefighters who work. Size of fire = lurking variable (effects both)
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Term
| strong linear correlation |
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Definition
one of the following may be true:
- direct cause and effect relationship between the two variables
- reverse cause and effect relationship between the two
- relationship may be caused by a third variable
- may be caused by the interactions of several other variables
- the apparent relationship may be strictly coincidence
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Term
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Definition
relationship between two variables as an algebraic expression describing the mathematical relationship between x and y
- linear: y=b0 + b1x
- quadratic: y=a + bx+cx2
- exponential: y = a(bx)
- logarithmic: y=alogbx
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Term
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Definition
slope = B1
B1=(Σ(x-xbar)(y-ybar))/Σ(x-xbar)2
B1= SS(xy)/SS(x) |
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Term
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Definition
y-intercept = B0
B0=(Σy-(b1*Σx))/n
B0=ybar-(B1*xbar) |
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