Chapter 8, Problem 1DQ

Figure 8.9 shows summer air visibility measurements for Denver, Colorado. The acceptable visibility standard is 100, with readings above 100 indicating clean air and good visibility, and readings below 100 indicating temperature inversions caused by forest fires, volcanic eruptions, or collisions with comets.

1. Is a trend evident in the data? Which time-series techniques might be appropriate for estimating the average of these data?
2. A medical center for asthma and respiratory diseases located in Denver has great demand for its services when air quality is poor. If you were in charge of developing a short-term (say, 3-day) forecast of visibility, which causal factor(s) would you analyze? In other words, which external factors hold the potential to significantly affect visibility in the short term?
3. Tourism, an important factor in Denver’s economy, is affected by the city s image. Air quality, as measured by visibility, affects the city’s image. If you were responsible for development of tourism, which causal factor(s) would you analyze to forecast visibility for the medium term (say, tile next two summers)?
4. The federal government threatens to withhold several hundred million dollars in Department of Transportation funds unless Denver meets visibility standards within 8 years. How would you proceed to generate a long-term judgment forecast of technologies that will be available to improve visibility in the next 10 years?

Summary Introduction

Interpretation:Whether trend is evident in the data or not and the most appropriate time-series techniques for estimating the average of the data should be determined.

Concept Introduction: Trend is the tendency in data for a particular time may be increasing or decreasingpattern of data series at a particular time is called time series.

Answer to Problem 1DQ

No trend was identified in the given information.

Explanation of Solution

Given information:Calculating trend from data and time series techniques as appropriate using standard of acceptable visibility as 100, indicating above 100 of clean air and good visibility and below 100 of temperature inversions

Given information has no trend as there is no increase or decrease between two consecutive years because when a trend cannot be made when prediction is not possible.Prediction cannot be made for natural calamities like fire in the forest, comets crashing, and volcano explosions. Here the simple average method is appropriate

Simple average method is a method of time series and calculating moving average as it a division of summation of observations by number of appearances.

Summary Introduction

Interpretation:The external factors affecting the potential of significant visibility in the short term should be determined.

Concept Introduction: External factors are factors that are outside necessary to forecast in recent times

Answer to Problem 1DQ

External factors of weather,seasonaland festive factors the visibility for asthma diseases

Explanation of Solution

Given information:Medical center for asthma and respiratory diseases is in great demand for its service in Denver when air quality is poor.

Affecting external factors are as follows

Weather factor: As visibility bases, weather reports should be collected.

Seasonal factor: As visibility is being affected in the winter season due to fog, it should be considered.

Festive factor: As festive has firecrackers and smoke which affects the visibility, they should be considered before forecasting.

All the above factors majorly have effects like asthma and other diseases.

Summary Introduction

Interpretation:The casual factors affecting for visibility of air of tourism in medium term to Denver’s economy need to be determined.

Concept Introduction: General factors affecting the visibility is casual factors and essential in forecasting the visibility in forth coming two summers

Answer to Problem 1DQ

General factors are average visibility and pollution factor.

Explanation of Solution

Given information:Tourism in Denver is affected by the city’s image as air quality changes.

Following are the general factors affecting the visibility

Average visibility factor:It considers the visibility between two forthcoming summers

Pollution factor:Before forecasting, air pollution in weather should be considered

Summary Introduction

Interpretation:The long term judgment and the forecast visibility in the transportation department is to be determined of Denver’s in next 10 years

Concept Introduction: Long run judgments forecasting refers to the anticipation of any happenings in future time frame in the given time period of 8 or 10 years.

Answer to Problem 1DQ

Understanding the invention of carbon absorbing machine.

Explanation of Solution

Given information:The federal government has threatened to withhold several hundred million dollars in Department of Transportation funds.

There is carbon dioxide in air which causes pollution. Manager invented carbon-absorbing machine (which is in ending phase) by going through various science journals absorbing 40 % carbon from polluted air to make air pollution free. Visibility can be increased by pollution free standards.