Explore BrainMass

Time Series Analysis

A time series is a sequence of data points measured at successive points in time spaced at uniform time intervals.  Time series are used in statistics, signal processing, pattern recognition, econometrics, mathematical finance and many more. Time series analysis comprises methods for analyzing time series data in order to extract meaningful statistic and other characteristics of the data. Time series forecasting is the use of a model to predict future values based on previously observed values. Regression analysis is often employed in a way to test theories that the current values of one or more independent time series affect the current value of another time series, this analysis of time series is not called “time series analysis”. It focuses on comparing values of time series at different points in time.

Time series data have a natural temporal ordering. It makes time series analysis distinct from other data analysis problems in which there is no natural ordering of the observations. Time series analysis is also distinct from spatial data analysis where the observations typically relate to geographical locations. Time series models will often make use of the natural one-way ordering of time so that values for a given period will be expressed as deriving in some way from past values, rather than from future values. Time series analysis can be applied to real-valued, continuous data, discrete numeric data or discrete symbolic data.

Models for time series data can have many forms and represent different processes. When modeling variations in the level of a process, the three broad classes of practical importance are the autoregressive models, the integrated models and the moving average models. 

Steps on Calculating Uniform Annual Cost

An alternative has a discounted project cost of $12,345,000 with a discounted salvage value of $1,750,000. The estimate was in constant dollars and the discounting used end-of-year factors. While the period of analysis is 5 years, the alternative only provides benefits for the last 4 years. Calculate the uniform annual cost.

Constructing a p chart for given data using excel

Researchers at Miami University in Oxford, Ohio, investigated the use of charts to monitor the market share of a product and to document the effectiveness of marketing promotions, Market share is defined as the company's proportion of the total number of products sold in a category. If a p chart based on a company's market share


During the dinner hour, the distribution of the inter-arrival time of customers at a restaurant is estimated to be as shown below. The mode of payment and the service times of the cash and credit card customers are shown in the following tables. Complete the tables and simulate the system for 20 customer arrivals and determine

Various questions on quantitative analysis for management

I have most of the answers, I just need to make sure I know how to read the charts/data, with the proper steps. I want to be able to study the correct info. The question is on the topic of quantitative analysis for management and includes questions about finding the critical path and calculating slack time.

Smoothing Techniques

I have been using basic smoothing techniques such as moving average, median smoothing and exponential smoothing to generate forcasts for the time series in the attached excel file. I would like to know if more advanced smoothing techniques would give better results. The columns in the file are a time series of performance fig

Autocorrelation Function and Partial Autocorrelation Function

The instructor has "covered" Autocorrelation Function (ACF) and Partial Autocorrelation Function (PACF), but I have not yet grasped a full understanding. Could you give me a cursory explanation now? I do know how to call up the ACF and PACF graphs but her explanation of how to use them and what they mean was not very clear.

Moving Averages for the Time Series

The following data represent revenues in thousands of dollars for a manufacturer of small electric appliances. a. Calculate the moving averages for this time series. Moving Year Quarter Revenues Q Average 1996 1 514

Time series Analisis

Question 1 Suppose that {Y_t} is stationary with autocovariance function ?_k. a) Show that W_t=?Y_t=Y_t-Y_(t-1) is stationary by finding the mean and autocovariance function for {W_t} . b) Show that U_t=?^2 Y_t=?[Y_t-Y_(t-1) ]= Y_t-2Y_(t-1)+Y_(t-2) is stationary. (you need not find the mean and autocovariance function for

Time Series Analysis and Random Processes

Question 1: Simulate a completely random process of length 48 with independent, normal values. Plot the time series plot. Does it look "random"? Repeat this exercise several times with a new simulation each time. Question 2: Simulate a completely random process of length 48 with independent, t-distributed values each with 5

Time Series analysis

The following is a time series data set. Run a time-series analysis for projections of April 2009 in the Healthcare industry of Nashville. (Run in SPSS and just copy and paste results in microsoft word. Explain your results) 2006-Dec 55010 2006-Nov 55200 2006-Oct 54100 2006-Sep 54050

linear trend of time series

For the data of this exercise use the weighting constant  = 0.5 and exponential smoothing to determine the forecast for 2005. U.S. cellular phone subscribership has been reported as shown below for the 1993-2004 period Year Subscribers (millions) Year Subscribers (millions) 1993 16.0 1999 86.0 1994 24.1 2000 109.5 1995 3

Short-Term Forecasting

Data covering the most recent 30 days are given in the following table for the price per gallon of regular gasoline at a location station Day Price Day Price 1 2.53 16 2.46 2 2.35 17 2.6 3 1.91 18 2.1 4 2.2 19 2.01 5 1.77 20 2.14 6 3.26 21 2.03 7 1.63 22 2.68 8 2.73 23 2.59 9 2.41 24 2.99 10 2.72 25 2.94 11 2.87

How to do overall adequate at 0.05 level, moving average and 2 others questions

1. The overall model statistically adequate at a 0.05 level of significance for predicting sale price(y)? a. no, since some other t-tests for the individual variables are not significant. b. no since the standard deviation of the model is fairly large. c. yes, since none of the B -estimates are equal to 0. d. yes, since

Statistics Study Guide

Questions 12 - 19 refer to the attachment : Product sales since 1984 are: Year 1984 1985 1986 1987 1988 1989 1990 1991 1992 Sales 266 264 145 205 139 98 94 94 128 The least squares trend equation using the coded method is given: Y1 = 159.22 - 21.18X, where X is set equal to 0 for 1

Frequency distribution, stem and leaf plot, statistical graphs

1. The acreage of the 39 U.S. National Parks under 900,000 acres (in thousands of acres) is shown here. Construct a frequency distribution for the data using eight classes. Do a frequency distribution, you are constructing a table, not a graph. 41 66 233 775 169 36 338 233 236 64 183 61 13 308 77 520 77 27 217 5 650

Quantitative Methods (Stats) Multiple Choice & True/False Probs

1. Random numbers generated by a mathematical process instead of a physical process are pseudorandom numbers. (Points: 4) True False 2. Experimental outcomes must occur as numerical values in order to define their probability distribution. True False 3. Sample information with an effici

Overall long-term tendency

Which of the following terms describes the overall long-term tendency of a time series? a. Secular Trend b. Cyclical component c. Irregular component d. Seasonal component.

Time Series Models

Is it true that one of the important properties of time series models is that some sort of pattern in the data over time should be detected first and then used within the model? Please clarify.


In a Group Time Series design a) The subjects act as their own control. b) We can study situations where records are kept over time. c) Has the internal validity problem of "history". d) All are true

Type of design is noted.

Corinna studies the frequency of automobile fatalities in New York State before and after the passage of a law requiring the usage of seatbelts. What is this type of design?

Statistic Trends/Series

Please see below: Citing significant strides in math and science by women of all ethnic backgrounds, the College Broad says that the male-female gap on Scholastic Assessment Test scores continue to narrow among high school students. The average SAT scores for men and women from 1990 to 1994 are shown below: Verbal Men