
Financial Risk Manager Part 1
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A ski resort has come up with a model to predict the number of guests (given in hundreds) checking in throughout the year. The time series model contains both a trend and a seasonal component and is given by the following:
The trend component is reflected in variable , where .
Seasons are defined as follows:
| Season | Months | Dummy |
|---|---|---|
| Winter | December, January and February | β |
| Spring | March, April and May | |
| Summer | June, July and August | |
| Fall | September, October and November |
The model starts in April 2019, i.e., refers to May 2019. How many more guests are expected in April 2020 than in July of the same year?
Explanation:
Explanation
The model is given as:
Since we have three dummies and an intercept, quarterly seasonality is reflected by the intercept (10.5) plus the three seasonal dummy variables (, , and ).
If , then:
- April 2020 =
- July 2020 =
Note that April falls under (Spring season), while July falls under (Summer season).
Calculation for April 2020 ():
- Time component:
- Intercept:
- Spring dummy:
- Total:
Calculation for July 2020 ():
- Time component:
- Intercept:
- Summer dummy:
- Total:
Difference:
Since the number of guests is given in hundreds, the actual difference is:
Thus, the model predicts 1,590 guests in April and 1,560 guests in July, representing a difference of 30 guests._