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问题 1
a) 检查情节并描述尝试预测时可能出现的问题
鉴于此时间序列数据,未来的黄金价格。为这些问题提供解决方案。 (2
b) 为这些数据提供合适的预测方法。 (2 分)。

对于以下每个 ACF 图,它们是为 4 的时间序列数据获得的
a) 解释 ACF 图。 (2 分)。
b) 描述原始数据随着时间的推移可能会是什么样子。 (2 分)。
c) 该图可能表征什么样的变量(例如,股票价格、
汇率、温度等)? (2 分)。

问题 3
以下 ACF 图是为两个不同的月销售额的原始数据生成的
变量 A 和 B。
a) 解释哪个变量可能更容易预测。 (3 分)。
b) 解释如果这些是一个残差,你对 a) 部分的答案将如何改变
ARIMA 模型而不是“月销售额的原始数据”。 (3 分)。
变量 A:

问题 4
方差更稳定。 (3 分)。

Question 1
The below graph plots the daily prices of Gold over time.
a) Examine the plot and describe the issues that may arise when trying to forecast
future Gold prices given this time series data. Offer solutions to these issues. (2
b) Offer a suitable forecasting method for this data. (2 marks).

Question 2
For each of the below ACF plots which are obtained for a time series data of 4
different variables of interest:
a) Explain the ACF plot. (2 marks).
b) Describe what the raw data is likely to look like over time. (2 marks).
c) What kind of variable is this plot likely to characterise (e.g., stock prices,
exchange rates, temperature, etc.)? (2 marks).

Question 3
The following ACF plots were produced for raw data of monthly sales of two different
variables, A and B.
a) Explain which variable is likely to be easier to forecast. (3 marks).
b) Explain how your answer to part a) would change if these were residuals of an
ARIMA model instead of “raw data of monthly sales”. (3 marks).
Variable A:

Question 4
For the following time series plots, explain what type of transformation, if any, would make
the variance more stable. (3 marks).

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