scholarly journals Analyzing Ordinal Scales in Studies of Virtual Environments: Likert or Lump It!

2007 ◽  
Vol 16 (4) ◽  
pp. 439-446 ◽  
Author(s):  
Henry J. Gardner ◽  
Michael A. Martin
Keyword(s):  
Virtual Environments ◽  
Statistical Methods ◽  
Ad Hoc ◽  
Nonparametric Statistics ◽  
Continuous Data ◽  
Statistical Tools ◽  
Great Caution ◽  
Statistical Procedures ◽  
Survey Questions ◽  
Ordinal Scales

Likert scaled data, which are frequently collected in studies of interaction in virtual environments, demand specialized statistical tools for analysis. The routine use of statistical methods appropriate for continuous data in this context can lead to significant inferential flaws. Likert scaled data are ordinal rather than interval scaled and need to be analyzed using rank based statistical procedures that are widely available. Likert scores are “lumpy” in the sense that they cluster around a small number of fixed values. This lumpiness is made worse by the tendency for subjects to cluster towards either the middle or the extremes of the scale. We suggest an ad hoc method to deal with such data which can involve a further lumping of the results followed by the application of nonparametric statistics. Averaging Likert scores over several different survey questions, which is sometimes done in studies of interaction in virtual environments, results in a different sort of lumpiness. The lumped variables which are obtained in this manner can be quite murky and should be used with great caution, if at all, particularly if the number of questions over which such averaging is carried out is small.

scholarly journals Statistical Methods for Solving Transportation Problems

2019 ◽  
Vol 25 (2) ◽  
pp. 10-13
Author(s):  
Alina Baboş
Keyword(s):  
Linear Programming ◽  
Statistical Methods ◽  
Approximation Method ◽  
Transportation Problem ◽  
Feasible Solution ◽  
Basic Feasible Solution ◽  
Statistical Tools ◽  
Numerical Examples ◽  
North West ◽  
Shipping Cost

Abstract Transportation problem is one of the models of Linear Programming problem. It deals with the situation in which a commodity from several sources is shipped to different destinations with the main objective to minimize the total shipping cost. There are three well-known methods namely, North West Corner Method Least Cost Method, Vogel’s Approximation Method to find the initial basic feasible solution of a transportation problem. In this paper, we present some statistical methods for finding the initial basic feasible solution. We use three statistical tools: arithmetic and harmonic mean and median. We present numerical examples, and we compare these results with other classical methods.

Discussion of Statistical Methods for Determining Purity of Citrus Juice

1983 ◽  
Vol 66 (3) ◽  
pp. 781-788 ◽  
Author(s):  
Morton B Brown ◽  
Eli Cohen
Keyword(s):  
Statistical Methods ◽  
Fruit Juice ◽  
Statistical Test ◽  
Good Chance ◽  
Citrus Juice ◽  
Unknown Sample ◽  
Statistical Procedures

Abstract It is difficult to develop statistical methods to determine the purity of fruit juice because of country-to-country and environmental differences among fruit. A test of an unknown sample of citrus juice can err in 2 ways: Pure juice can mistakenly be rejected as adulterated, or adulterated juice can be accepted as pure. Many of the statistical procedures proposed maymisclassify a high proportion of samples of pure juice as adulterated. It is necessary to develop a statistical test that will only rarely reject samples of pure juice, and will have a good chance of rejecting adulterated juice.

scholarly journals Evaluation of mechanistic and statistical methods in forecasting influenza-like illness

2018 ◽  
Vol 15 (144) ◽  
pp. 20180174 ◽  
Author(s):  
Sasikiran Kandula ◽  
Teresa Yamana ◽  
Sen Pei ◽  
Wan Yang ◽  
Haruka Morita ◽  
...  
Keyword(s):  
Statistical Methods ◽  
Seasonal Influenza ◽  
Ad Hoc ◽  
Weighted Average ◽  
Surveillance Systems ◽  
Domain Experts ◽  
Influenza Activity ◽  
The Usa ◽  
The Individual

A variety of mechanistic and statistical methods to forecast seasonal influenza have been proposed and are in use; however, the effects of various data issues and design choices (statistical versus mechanistic methods, for example) on the accuracy of these approaches have not been thoroughly assessed. Here, we compare the accuracy of three forecasting approaches—a mechanistic method, a weighted average of two statistical methods and a super-ensemble of eight statistical and mechanistic models—in predicting seven outbreak characteristics of seasonal influenza during the 2016–2017 season at the national and 10 regional levels in the USA. For each of these approaches, we report the effects of real time under- and over-reporting in surveillance systems, use of non-surveillance proxies of influenza activity and manual override of model predictions on forecast quality. Our results suggest that a meta-ensemble of statistical and mechanistic methods has better overall accuracy than the individual methods. Supplementing surveillance data with proxy estimates generally improves the quality of forecasts and transient reporting errors degrade the performance of all three approaches considerably. The improvement in quality from ad hoc and post-forecast changes suggests that domain experts continue to possess information that is not being sufficiently captured by current forecasting approaches.

Statistics and the nature of depression

1993 ◽  
Vol 23 (4) ◽  
pp. 871-889 ◽  
Author(s):  
G. Dunn ◽  
P. Sham ◽  
D. Hand
Keyword(s):  
Clinical Trials ◽  
Maintenance Therapy ◽  
Statistical Methods ◽  
Beck Depression Inventory ◽  
Rating Scale ◽  
Meta Analysis ◽  
Critical Examination ◽  
Statistical Tools ◽  
Hamilton Rating Scale

SynopsisA critical examination is made of the role that statistical methods have played in the understanding of depression. The development of instruments for measuring depression is illustrated by reference to the Beck Depression Inventory and the Hamilton Rating Scale. The controversy over the existence of one or two types of depression is examined from the perspective of the statistical tools used. Some of the problems in studies of the heritability of depression are outlined. The development of clinical trials of depression is examined, with particular reference to ECT and maintenance therapy, and the role of meta-analysis is discussed.

The Sense of Presence within Auditory Virtual Environments

1996 ◽  
Vol 5 (3) ◽  
pp. 290-301 ◽  
Author(s):  
Claudia Hendrix ◽  
Woodrow Barfield
Keyword(s):  
Virtual Environments ◽  
Virtual Environment ◽  
Sound Source ◽  
Virtual World ◽  
Auditory Display ◽  
Auditory Cues ◽  
Navigation Task ◽  
Perceived Realism ◽  
Sense Of Presence ◽  
Survey Questions

Two studies were performed to investigate the sense of presence within stereoscopic virtual environments as a function of the addition or absence of auditory cues. The first study examined the presence or absence of spatialized sound, while the second study compared the use of nonspatialized sound to spatialized sound. Sixteen subjects were allowed to navigate freely throughout several virtual environments and for each virtual environment, their level of presence, the virtual world realism, and interactivity between the participant and virtual environment were evaluated using survey questions. The results indicated that the addition of spatialized sound significantly increased the sense of presence but not the realism of the virtual environment. Despite this outcome, the addition of a spatialized sound source significantly increased the realism with which the subjects interacted with the sound source, and significantly increased the sense that sounds emanated from specific locations within the virtual environment. The results suggest that, in the context of a navigation task, while presence in virtual environments can be improved by the addition of auditory cues, the perceived realism of a virtual environment may be influenced more by changes in the visual rather than auditory display media. Implications of these results for presence within auditory virtual environments are discussed.

scholarly journals Impact of Lockdown in the FMCG sector of the Indian Stock Market – Analysis using Statistical Methods

2021 ◽  
Vol 12 (1S) ◽  
pp. 647-654
Author(s):  
M. Vivek Prabu, Et. al.
Keyword(s):  
Stock Market ◽  
Statistical Methods ◽  
Global Economy ◽  
Market Analysis ◽  
Negative Trend ◽  
High Demand ◽  
Statistical Tools ◽  
Indian Economy ◽  
Indian Stock Market ◽  
The Impact

The Covid19 outbreak has shattered the Global economy and Indian economy too had got no exemption from it. Despite the GDP of India moving in the negative trend, very few sectors like Pharmaceutical and FMCG have shown some positive signs because of this pandemic and the lockdown followed by it. Consumer staples will always remain essential irrespective of the economical movement. In particular, during the tougher times, whenever there arises an unprecedented scenario, the humankind will always try to safeguard itself and in turn that will certainly cause a high demand in the FMCG sector. In this paper, we will be analysing the impact of lockdown in the movement of the FMCG sector using some of the Statistical tools

scholarly journals Fuzzy Based Priority Ad Hoc on Demand Multipath Distance Vector Stable Routing protocol (FPAOMDV)

2021 ◽  
Author(s):  
Swati Atri ◽  
Sanjay Tyagi
Keyword(s):  
Fuzzy Logic ◽  
Routing Protocol ◽  
Ad Hoc ◽  
Data Transfer ◽  
Continuous Data ◽  
Route Selection ◽  
On Demand ◽  
Multiple Paths ◽  
Distance Vector ◽  
Stable Routing

Abstract Mobile ad-hoc networks are the most uncertain type of networks. Uncertainty occurs due to the mobile nature of the nodes, continuous consumption of energy and bandwidth results in unpredictable state of nodes. In this situation making an efficient, reliable and stable route selection is a challenging task and an open research problem aiming to provide continuous data transfer between source and destination node. Multipath routing protocol ensures reliable communication by providing multiple paths between source and destination nodes. To choose the best one among different alternative paths is the problem addressed by this paper. For this purpose fuzzy logic (multi valued logic) has been used. Fuzzy logic is a soft computing technique which is able to make precise and accurate decision in multi variable, uncertain and imprecise situation. Here, firstly Multipath Priority Based Route Discovery Mechanism (MPRDM) has been used to generate multiple paths between the two nodes participating in the communication. MPRDM calculates individual priority value for every RREP packet and assigns it to the different obtained routes. Further, in this paper fuzzy logic has been used for designing fuzzy route selection controller for Fuzzy Logic Based Stable Route Selection mechanism (FLSRSM) which calculates stability value of different routes based on priority value, average mobility and residual energy along the paths FLSRSM is able to make selection of best stable path based on the highest value of stability metric. This mechanism has been used to propose fuzzy based priority ad-hoc on demand multipath distance vector stable routing protocol (FPAOMDV) that provide stability, reliability and selects the route that has sufficient amount of energy to hold continuous data transfer. In Simulation results on NS2, the proposed protocol outperforms other compared routing protocols in terms of delay, throughput, PDR and overhead.

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