correct answers
For Simple moving average, longer periods are _________ than shorter periods.
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Smoother or less smooth - ANSWER: ➡ Smoother o o o o o oo o
Creates a new time series from the original data by averaging adjacent values.
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helps illuminate how the data is varying over time.
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Affected by outliers and peaks. o o o o
Doesn't work well when there are strong seasonal, trend or cyclical components. - ANSWER:
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➡ Simple Moving Average
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values that are closest to the estimated value get the most weight in the moving average and
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values that are farther away get less.
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adjust weight between recent and historic data. - ANSWER: ➡ Simple exponential smoothing
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A smaller a (alpha) would be __________________.
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Smoother or more flat or less smooth - ANSWER: ➡ Smoother
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Time series where we add in columns containing lags.
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Good for quarterly lag. - ANSWER: ➡ Autoregressive models
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We can cautiously predict a little further away from the data. Better at fitting series that have
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trend, cyclical, and seasonal components.
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Linear
- Additive: SLR
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- Exponential: SLR but log(y)
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, Quarters: Add indicator variables - ANSWER: ➡ Multiple Regression Models
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the best prediction is the most recent point. Time series.
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Sometimes described as white noise. - ANSWER: ➡ Random walk o o o o o o oo o o
Allow us to compare two or more means.
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Ho: M1 = M2 = Mk (No difference in treatments)
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Ha: At least one population mean is different from the rest. - ANSWER: ➡ One way ANOVA
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an extra variable added to help predict this cyclical trend. - ANSWER: ➡ exogenous variable
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estimates how much the means vary. o o o o o
gets bigger by adding another group. - ANSWER: ➡ sum of squares treatment
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estimates how much variation there is within each group. - ANSWER: ➡ sums of squares error
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The confidence level is found by using 1 - a/j
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where j is the number of comparisons. - ANSWER: ➡ Bonferroni method
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two factors with multiple levels.
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We look at effects using an interaction plot.
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Interaction present -> multiple comparisons. o o o o
No interaction present-> look at main effects. - ANSWER: ➡ two way ANOVA
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when the effects of one factor are NOT similar across all levels of the other factor. - ANSWER: ➡
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interaction
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