Financial Risk Manager Part 1

Financial Risk Manager Part 1

Get started today

Ultimate access to all questions.


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:

yt=0.2Γ—Timet+10.5+3.0Γ—D2t+2.1Γ—D3t+2.8Γ—D4ty_t = 0.2 \times \text{Time}_t + 10.5 + 3.0 \times D_{2t} + 2.1 \times D_{3t} + 2.8 \times D_{4t}

The trend component is reflected in variable TIME(t)\text{TIME}_{(t)}, where (t)=month(t) = \text{month}.

Seasons are defined as follows:

SeasonMonthsDummy
WinterDecember, January and Februaryβ€”
SpringMarch, April and MayD2tD_{2t}
SummerJune, July and AugustD3tD_{3t}
FallSeptember, October and NovemberD4tD_{4t}

The model starts in April 2019, i.e., y(T+1)y_{(T+1)} refers to May 2019. How many more guests are expected in April 2020 than in July of the same year?

TTanishq



Explanation:

Explanation

The model is given as:

yt=0.2Γ—Timet+10.5+3.0Γ—D2t+2.1Γ—D3t+2.8Γ—D4ty_t = 0.2 \times \text{Time}_t + 10.5 + 3.0 \times D_{2t} + 2.1 \times D_{3t} + 2.8 \times D_{4t}

Since we have three dummies and an intercept, quarterly seasonality is reflected by the intercept (10.5) plus the three seasonal dummy variables (D2D_2, D3D_3, and D4D_4).

If y(T+1)=MayΒ 2019y_{(T+1)} = \text{May 2019}, then:

  • April 2020 = y(T+12)y_{(T+12)}
  • July 2020 = y(T+15)y_{(T+15)}

Note that April falls under D(2t)D_{(2t)} (Spring season), while July falls under D(3t)D_{(3t)} (Summer season).

Calculation for April 2020 (y(T+12)y_{(T+12)}):

  • Time component: 0.2Γ—12=2.40.2 \times 12 = 2.4
  • Intercept: 10.510.5
  • Spring dummy: 3.0Γ—1=3.03.0 \times 1 = 3.0
  • Total: 2.4+10.5+3.0=15.92.4 + 10.5 + 3.0 = 15.9

Calculation for July 2020 (y(T+15)y_{(T+15)}):

  • Time component: 0.2Γ—15=3.00.2 \times 15 = 3.0
  • Intercept: 10.510.5
  • Summer dummy: 2.1Γ—1=2.12.1 \times 1 = 2.1
  • Total: 3.0+10.5+2.1=15.63.0 + 10.5 + 2.1 = 15.6

Difference:

y(T+12)βˆ’y(T+15)=15.9βˆ’15.6=0.3y_{(T+12)} - y_{(T+15)} = 15.9 - 15.6 = 0.3

Since the number of guests is given in hundreds, the actual difference is: 0.3Γ—100=30Β guests0.3 \times 100 = 30 \text{ guests}

Thus, the model predicts 1,590 guests in April and 1,560 guests in July, representing a difference of 30 guests._

Comments

Loading comments...