﻿ 代写统计课业作业 Stat4603/5504代写 - R语言代写, 统计代写

# 代写统计课业作业 Stat4603/5504代写

2022-08-03 11:11 星期三 所属： R语言代写 浏览：70 ## Total marks: 100

### 1.[10 marks]

Fit a seasonal ARIMA model of your choice to the monthly unemployment data in unemp Go through the diagnostic checking and use the model to forecast the next 12 months.

### 2.[10 marks]

Fit a seasonal ARIMA model of your choice to Johnson and Johnson jj quarterly earnings. Remove the last four quarters from your data before fitting the model. Forecast these quarters. Compare forecasts and actual values.

### 3.Lagged regression with dependent errors  代写统计课业作业

Let Strepresent the monthly sales data in sales file (n = 150) and let Ltbe the leading indicator data in lead file.

(a) [10 marks] Fit an ARIMA model to St . Discuss your model fitting in a step-by-step fashion, presenting your (A) initial examination of the data, (B) transformation if necessary, (C) initial identification of the dependence orders and degree of differencing, (D) parameter estimation, (E) residual diagnostics, and model choice.

(b) [5 marks] Use CCF and lags plots between ∆St and ∆Lt to argue that a regression of ∆St on ∆Lt3 is reasonable. [Note that in lag2.plot(x, y), the first series x gets lagged].

(c) [10 marks] Fit a regression model ∆St = β0 + β1Lt3 + zt where zt is an ARMA process. (Explain how you decided on your model for zt).

### 4.[5 marks] Delayed signal  代写统计课业作业

In applications, we will often observe series containing a signal that has been delayed by some unknown time D, i.e.

xt = st + AstD + nt,

where st and nt are stationary and independent with zero mean and spectral densities fs and fn, respectively.The delayed signal gets multiplied by unknown constant A. Show that

fx(ω) = [1 + A2 + 2A cos(2πωD)]fs(ω) + fn(ω).

### 5.[5 marks] Cycles in chicken price

Analyse the chicken price data chicken using frequency-domain approach. What are the interesting cycles that can be discovered? (there is one obvious. To what does it correspond?)

### 6.Salt concentration levels  代写统计课业作业

The levels of salt concentration known to have occurred over rows, corresponding to the average temperature levels are in salt and saltemp.

(a) [5 marks] Plot the two series and then identify the dominant frequencies by performing separate spectral analyses on the two series. Interpret your findings.

(b) [5 marks] Analyse the coherence between the temperature and salt data. Discuss your findings.

### 7.Frequency analysis of weather factors  代写统计课业作业

The data set climhyd contains 454 months of measured values for six climatic variables: (i) air temperature Temp, (ii) dew point DewPt, Cloud cover CldCvr, (iv) wind speed WndSpd, (v) precipitation Precip, and (vi) inflow Inflow, at Lake Shasta in California. We would like to look into possible relations among the weather factors and between the weather factors and the inflow to Lake Shasta.

### 8.[5 marks]

Plot GNP (Global National Product) data gnp, and then test for a unit root against the alternative that the process is explosive (random walk).

### 9.[10 marks]  代写统计课业作业

The stats package of R contains the daily closing prices of four major European stock markets; (type help(EustockMarkets)) for details. Fit a GARCH model to the returns of one of these series and discuss your findings. Note: These are actual values, and not returns. Hence data must be transformed prior to the modelling. 