Preview

Mr. David O. Nwafor

Powerful Essays
Open Document
Open Document
4943 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Mr. David O. Nwafor
Statistical Concepts Series

Radiology

Seema S. Sonnad, PhD

Describing Data: Statistical and Graphical Methods1
An important step in any analysis is to describe the data by using descriptive and graphic methods. The author provides an approach to the most commonly used numeric and graphic methods for describing data. Methods are presented for summarizing data numerically, including presentation of data in tables and calculation of statistics for central tendency, variability, and distribution. Methods are also presented for displaying data graphically, including line graphs, bar graphs, histograms, and frequency polygons. The description and graphing of study data result in better analysis and presentation of data.
©

Index terms: Data analysis Statistical analysis Published online before print 10.1148/radiol.2253012154 Radiology 2002; 225:622– 628
1

From the Department of Surgery, University of Michigan Medical Center, Ann Arbor. Received January 14, 2002; revision requested March 2; revision received May 20; accepted June 14. Address correspondence to the author, Department of Surgery, University of Pennsylvania Health System, 4 Silverstein, 3400 Spruce St, Philadelphia, PA 19104-4283 (e-mail: seema.sonnad@uphs .upenn.edu). RSNA, 2002

RSNA, 2002

©

A primary goal of statistics is to collapse data into easily understandable summaries. These summaries may then be used to compare sets of numbers from different sources or to evaluate relationships among sets of numbers. Later articles in this series will discuss methods for comparing data and evaluating relationships. The focus of this article is on methods for summarizing and describing data both numerically and graphically. Options for constructing measures that describe the data are presented first, followed by methods for graphically examining your data. While these techniques are not methodologically difficult, descriptive statistics are central to the process of organizing and summarizing



References: 1. Heverhagen JT, Muller D, Battmann A, et al. MR hydrometry to assess exocrine function of the pancreas: initial results of noninvasive quantification of secretion. Radiology 2001; 218:61– 67. 2. Kaus MR, Warfield SK, Nabavi A, Black PM, Jolesz FA, Kikinis R. Automated segmentation of MR images of brain tumors. Radiology 2001; 218:586 –591. 3. Deliganis AV, Fisher DJ, Lam AM, Mara- 6. 7. villa KR. Cerebrospinal fluid signal intensity increase on FLAIR MR images in patients under general anesthesia: the role of supplemental O(2). Radiology 2001; 218: 152–156. Jackman RJ, Burbank F, Parker SH, et al. Stereotatic breast biopsy of nonpalpable lesions: determinants of ductal carcinoma in situ underestimation rates. Radiology 2001; 218:497–502. Fain SB, King BF, Breen JF, Kruger DG, Riederer SJ. High-spatial-resolution contrastenhanced MR angiography of the renal arteries: a prospective comparison with digital subtraction angiography. Radiology 2001; 218:481– 490. Bielak LF, Sheedy PF II, Peyser PA. Automated segmentation of MR images of brain tumors. Radiology 2001; 218:224 –229. Tombach B, Bremer C, Reimer P, et al. Renal tolerance of a neutral gadolinium chelate (gadobutrol) in patients with chronic renal failure: results of a randomized study. Radiology 2001; 218:651– 657. 628 Radiology December 2002 Sonnad

You May Also Find These Documents Helpful

  • Good Essays

    Project for Math533

    • 1861 Words
    • 8 Pages

    Introduction | Project Part A: Exploratory Data Analysis | Project Part A: Grading Rubric | Project Part B: Hypothesis Testing and Confidence Intervals | Project Part B: Grading Rubric | Project Part C: Regression and Correlation Analysis | Project Part C: Grading Rubric…

    • 1861 Words
    • 8 Pages
    Good Essays
  • Good Essays

    Fv1 Task 4

    • 514 Words
    • 3 Pages

    The results would be cataloged and compiled with and a mean score for each group. An analysis of variance (ANOVA) would be performed to compare the data between the three groups. Additional analysis utilizing a two-way chi-square formula to determine statistical differences between the variables of the three groups would be required utilizing the appropriate software. Associations between variables would be calculated using contingency coefficient analysis. Minimum statistical power would be set at 0.05 for Type I errors and 0.20 for Type II errors. The data scientist would be responsible for completing the data analysis once collected and cataloged.…

    • 514 Words
    • 3 Pages
    Good Essays
  • Good Essays

    stat 202 cheat sheet

    • 509 Words
    • 3 Pages

    r2 = fraction of variation in one variable that is explained by least-squares on the other variable…

    • 509 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    Summarize the data collected using descriptive statistics. Descriptive statistics should be in the forms of frequency distribution table, measures of mean, median, mode, standard deviation, and graphical display of data.…

    • 362 Words
    • 2 Pages
    Satisfactory Essays
  • Good Essays

    Even an appropriate chart type is selected, issues such as scaling, suitable titles and legend types must be considered carefully to ensure effective communication of the data so that it can be interpreted to aid decision making. Data is usually presented in digital table form, sometimes printed out only from the spreadsheet. While this presentation style provides detailed figures, it is not the efficient way to provide and disseminate information. It may be emphasizing some key information, or to emphasize the relationship between certain data or to identify trends. Appropriately presenting data in the form of graphs or graphs can be a useful analysis tool and this can facilitate the decision-making process if the data is effectively interpreted. It allows the user to create charts or graphs that look very professional and let decision makers review data…

    • 661 Words
    • 3 Pages
    Good Essays
  • Satisfactory Essays

    Typically, there are two general types of statistic that are used to describe data. Measures of central tendency are ways of describing the central position of a frequency distribution for a group of data. Measures of spread are ways of summarizing a group of data by describing how spread of the scores. Week 4’s assignment was to…

    • 415 Words
    • 3 Pages
    Satisfactory Essays
  • Powerful Essays

    BUS 308 Week 5 Final Paper

    • 1142 Words
    • 4 Pages

    Descriptive statistics are typically utilized for describing the general features of the information received from a study. The results provide a brief summary of sample and measures. This type of statistics along with a simple graphic aid, creates the basis for nearly all quantitative data analysis. It is also used for presenting quantitative descriptions of data in a comprehensive and manageable form (Schlaifer, 1982). In a research study, there is a possibility of several different measures or it can be a scenario where we are able to…

    • 1142 Words
    • 4 Pages
    Powerful Essays
  • Good Essays

    Nordqvist, C. (2010, Febuary 13). MediLexicon International Ltd. Retrieved Oct 3, 2011, from Medical News Today: http://www.medicalnewstoday.com…

    • 800 Words
    • 4 Pages
    Good Essays
  • Best Essays

    Framework For Praxis

    • 1985 Words
    • 7 Pages

    Hamric, A. B., Hanson, C. M., Tracy, M. F., & O’Grady, E. T. (2014). Advanced practice…

    • 1985 Words
    • 7 Pages
    Best Essays
  • Better Essays

    Roles and Functions Paper

    • 426 Words
    • 2 Pages

    * Hedlund, Nancy; Esparza, Angelina; Calhoun, Elizabeth; Yates, Jerome. Physician Executive. Sep/Oct2012, Vol. 38 Issue 5, p6-12. 6p. 1 Color Photograph, 1 Diagram.…

    • 426 Words
    • 2 Pages
    Better Essays
  • Good Essays

    Crohn's Disease

    • 1705 Words
    • 7 Pages

    Secko, D. (2005). CMAJ: Canadian Medical Association Journal, March 15, 2005, v172, i6, p738 (2). Retrieved from Infotrac Database on the University of Phoenix Library on November 17, 2005.…

    • 1705 Words
    • 7 Pages
    Good Essays
  • Good Essays

    Food Insecurity in Canada

    • 936 Words
    • 4 Pages

    Food insecurity is a social determinant of health that is becoming more prevalent in Canadian society. Food security is an important aspect of public health in which there is growing evidence between the association of food insecurity and poorer health outcomes. According to Raphael (2009), food insecurity can be defined as “the inability to acquire or consume an adequate diet quality or sufficient quantity of food in socially acceptable ways, or the uncertainty that one will be able to do so” (p. 188). One would not think that in a higher income country such as Canada that food insecurity would even be a public health concern, but according to Health Canada (2012) 7.2% of Canadian households were food insecure between the years 2007 and 2008. In addition, food insecurity was positively correlated with lower income households. According to Health Canada (2012) 55.5% of food insecure households main source of income was from social assistance.…

    • 936 Words
    • 4 Pages
    Good Essays
  • Better Essays

    JAMA: The Journal of the American Medical Association Issue: Volume 285(20), 23/30 May 2001, pp 2622-2628…

    • 1151 Words
    • 5 Pages
    Better Essays
  • Better Essays

    Uses of Statistics

    • 1057 Words
    • 5 Pages

    The use of statistics has been proven to assist the understanding of information, data, in many ways. Statistical information is not just collected, but it is also organized and quantified, providing a clearer picture for further study. This writer will explain how statistics are used in my personal workplace, and describe aspects of the statistics used.…

    • 1057 Words
    • 5 Pages
    Better Essays
  • Better Essays

    Heartache Kill

    • 751 Words
    • 4 Pages

    Virani, Salim S., A. Nasser Khan MD,Cesar E. Mendoza MD, Alexandre C. Ferreira MD, and…

    • 751 Words
    • 4 Pages
    Better Essays