Recall the moving average model dt = et − θet−1, where et are
independent with mean...
Recall the moving average model dt = et − θet−1, where et are
independent with mean 0 and variance σ2. Find its autocorrelation
function ρk = Cor(dt,dt−k).
Consider the model Yt = ΦYt−3 + et − θet−1, where et has
variance σ 2 .
(a) Identify Yt as a certain SARIMA(p, d, q) × (P, D, Q)s model.
That is, specify each of p, d, q, P, D, Q, and s. You may assume
that Φ < 1.
(b) Find the variance of Yt .
(c) What are the forecasts for Yt+1 and Yt+4?
(d) What are the error variances for your forecasts above?
(e) If σ...
5. The population of certain small organism grows according to
the model: dy/dt = 5y where y=20 when t=0
t is measured in months. a) Construct the specific function for
y. b) Find how many in the population of this organism after 8
months. c) Determine how many months until there are 228 of this
organism. Round to the nearest 0.1
What are the differences between autoregressive and moving
average models? Consider the following: model specifications,
stationarity, the shapes of their autocorrelation and partial
autocorrelation functions.
Consider the model as yt= βyt-1
+et, which describes the dynamics of price of a
company’s stock (y).
a. Assuming that et has zero mean, constant variance
σe2 and is not serially correlated, obtain
expressions for E(yt), var(yt) and
cov(yt, yt-1 ) and the first-order auto
correlation coefficient. Does y represent a stationary process?
Explain briefly.
b. If now et follows an AR(1) process, that is
et =ρet-1 +vt, where vt
is white noise and 0 < ρ < 1,...
Let X1, …
, Xn be independent where Xi is normally
distributed with unknown mean µ and unknown variance o2 > 0.
Find the likelihood ratio test for testing that µ = 0
against
−∞ < µ < ∞.
Let X1, … , Xn be independent where
Xi is normally distributed with unknown mean µ and
unknown variance o2 > 0.
Find the likelihood ratio test for testing that µ = 0
against
−∞ < µ < ∞.
Question 1 contains the actual values for 12 periods (listed in
order, 1-12). In Excel, create forecasts for periods 6-13 using
each of the following methods: 5 period simple moving average; 4
period weighted moving average (0.63, 0.26, 0.08, 0.03);
exponential smoothing (alpha = 0.23 and the forecast for period 5 =
53); linear regression with the equation based on all 12 periods;
and quadratic regression with the equation based on all 12 periods.
Round all numerical answers to two...
according to the kinked demanded curve model, an oligopolistic
firm will produce where:
A: average total cost is minimized
B: price equals marginal cost
C: marginal revenue equals marginal cost
D: the demand curve intersects the average total cost curve