This website uses cookies to ensure you have the best experience. Learn more

Statistics Essay

2616 words - 11 pages

COMM 291
Midterm Review Package
Prepared by Angelica Cabrera

1. INTRODUCTION TO DATA AND VARIABLES Categorical vs. Quantitative Data Categorical Limited number – distinct categories No Quantitative Large number Yes

Possible values for variable Measurement units?

EXAMPLE. Which variables are quantitative and which are categorical? Employee # Age (years) Annual Income (in Performance 1,000s of dollars) Rating (1-5 scale) 5543 48 50 – 100 4.5 2431 34 20 – 49 3.9 7281 31 0 – 19 3.4

Job Type Management Clerical Maintenance

2. SURVEYS AND SAMPLING Population: _______ individuals with a common characteristic that you want to generalize about Parameter: fact or characteristic about ...view middle of the document...

What kind of sampling designs are the following? a) Select ten individuals from each sport team at UBC (Ex. hockey, basketball, rowing, etc.) b) Randomly select 50 athletes using their student numbers c) Randomly select a faculty and survey all of athletes in that faculty d) Select every third name in alphabetized list of all varsity sports athletes at UBC, starting with a random name 3. DISPLAYING AND DESCRIBING CATEGORICAL DATA  Best represented in a __________ graph

Contingency Tables  Counts can be converted into: _______ Percentages

__________ Percentages

EXAMPLE. A survey collected teenagers’ preferences for soft drinks. Soft Drink Male Female Total 142 Pepsi 55 87 249 Sprite 99 150 309 Coke 196 113 350 350 700 Total a) What percentage of teenagers preferred Pepsi? b) What percentage of teenagers who preferred Coke were males? c) Of teenagers who are females, what percentage preferred Sprite? Simpson’s Paradox: an association that holds for all of several groups can _________ direction when the data are combined to form a single group. 4. DISPLAYING AND DESCRIBING QUANTITATIVE DATA  Best represented in a _____________, and an alternative is a ____________________ plot Measures of Spread  Range = Maximum value – minimum value  Standard deviation (SD): “typical” distance from the data value to the mean  Variance = (SD)2  Percentile: value below which % of data values fall  IQR = Q3 – Q1

Measures of Centre 1. Mean: average of data 2. Median: middle of data 3. Mode: most frequent data value

COMM 291 Review Package prepared by Angelica Cabrera

2

Histogram Shapes Symmetric Left: Skewed Right:

Mean ___median

Mean ___median

Mean ___median

Best Measures of Centre and Spread   For symmetric distributions, use ___________ and ___________ For skewed distributions, use ___________ and ___________

Box-and-Whisker Plots  How to draw a box-and-whisker plot 1. Plot points given 2. Draw IQR 3. Find inner fences  Lower inner fence = Q1 – 1.5 (IQR)  Outer inner fence = Q3 + 1.5 (IQR) 4. Draw whiskers (last values within the inner fences) 5. Draw outliers (values outside inner fences)

EXAMPLE 2. Below is a five-number summary for hourly wages for managers at AEKI, a furniture store. Min Q1 Median Q3 Max 20.94 37.64 44.77 49.24 67.11 a) This distribution is skewed to the:

b) What is the IQR?

c) What is the lower inner fence?

d) What is the upper inner fence?

e) Where do the outliers lie? f) There was an error and the lowest hourly wage for sales managers was $18.15 instead of $20.94. How would this affect: The mean? __________ The median? __________ The range? __________ The IQR? __________

COMM 291 Review Package prepared by Angelica Cabrera

3

5. SCATTERPLOTS, CORRELATION, AND LINEAR REGRESSION Correlation (r): how strong the linear clustering is around a line       Only for _______________ data with a ____________ pattern -1 < r < +1 NO units Correlation of X and Y = Correlation...

Other Papers Like Statistics

Statistics Essay

3466 words - 14 pages descriptive statistics. Students will learn to apply business research and descriptive statistics in making better business decisions. Other topics include examination of the role of statistics in research, statistical terminology, the appropriate use of statistical techniques, and interpretation of statistical findings in business and research. Policies Faculty and students will be held responsible for understanding and adhering to all

Statistics Essay

3604 words - 15 pages Question catalogue: Statistics Self-Study Module Master's programme Media and Communication Science If you are master student of the master programme “Media and Communication Science” and have to fulfill the additional requirement: Self-Study Module Statistics, you have to answer these list of 42 questions. Please answer the following questions concerning statistical methods in social science briefly. Helpful information concerning the

Statistics

1134 words - 5 pages 1) The main purpose of descriptive statistics is to A. summarize data in a useful and informative manner B. make inferences about a population C. determine if the data adequately represents the population D. gather or collect data 2) The general process of gathering, organizing, summarizing, analyzing, and interpreting data is called A. statistics B. descriptive statistics C. inferential statistics D. levels of measurement 3) The

Statistics - 2264 words

2264 words - 10 pages distributed normally. The Histogram below as well as the Descriptive Statistics (Appendix 1, Table 1b) show that the data distribution is leptokurtic (kurtosis is 2,021) and negatively skewed (skewness -,240). We can determine several outliers (Appendix 1, Table 1c, Table 1d) with extreme ratios. In cases #46 and #178 JSL is more than the highest option provided in the questionnaire. That could be a mistake in data entering or the respondent wanted

Statistics - 1168 words

1168 words - 5 pages 3 ( HA: μ< 3 ) Challenges the status quo Never contains the “=”, “≤” or “≥” sign May or may not be accepted Is generally the hypothesis that is believed (or needs to be supported) by the researcher –a research hypothesis. • Test Statistics: Sample used to determine whether a hypothesis will be accepted or rejected. If

Statistics - 1105 words

1105 words - 5 pages relied on the collection of data to make decisions that propel the human race into the next era of technical development and business growth. The type of data varies as it can either be quantified or qualitative to meet the needs and purpose of the research. The age old question has always been which of the two is the most preferred methodology, but the real question should be how both mirror the theme of statistics to provide the closest range to

Statistics - 666 words

666 words - 3 pages 10/24/2011 Introduction The Sample Mean The Central Limit Theorem The Sample Variance Sampling Distribution from The Normal Distribution Sampling from A Finite Population ◦ Distribution of The Sample Mean ◦ Joint Distribution of X and S2 ◦ Approximate Distribution of The Sample Mean ◦ How Large A Sample Is Needed 2 1 10/24/2011 Recall definitions of: ◦ ◦ ◦ ◦ ◦ ◦ ◦ Population Sample Inferential statistics Sampling Random

Statistics - 1921 words

1921 words - 8 pages one has tertiary or professional qualifications) P(A)=8C1*12C2/20C3+8C2*12C1/20C3+ 8C3*12C0/20C3 =8*66/1140+28*12/1140+56/1140 =0.807 3. Explain in detail the following key statistical concepts. Where possible illustrate your explanation with a graph or drawing. a) Descriptive Statistics Descriptive statistics means basic features of the raw data. A set of descriptive is used to describe the concerned samples. Arithmetic mean

Statistics - 1894 words

1894 words - 8 pages BUSINESS STATISTICS ASSIGNMENT Project Title: Employee retention at D&Y consulting firm Section E: Group 2:Anshul Garg (11FN-015)-Finance Gokul Sudhakaran(11DM-039)-Marketing Kaviya .A. (11DM-057)- Marketing Nikhil Gagrani(11DM-089)- Marketing Sheth Dharmil Nirupam(11DM-147)-Marketing Taru(11IB-061)-International Business Submission Date:- 9th September,2011

Statistics - 1794 words

1794 words - 8 pages adolescents’ reported incidence of being victims or perpetrators or traditional and electronic bullying. a. Using this table as an example, explain the idea of a frequency table to a person who has never had a course in statistics. Frequency is how many times something has happened and of all of the possible results that can occur, and each result's respective chance of happening. So the frequency of the table would be how many times the

Statistics - 1778 words

1778 words - 8 pages ) c) Copy and paste your regression result below. SUMMARY OUTPUT | | | | | | | | | | | | | | | | | Regression Statistics | | | | | | | | Multiple R | 0,66669338 | | | | | | | | R Square | 0,444480063 | | | | | | | | Adjusted R Square | 0,428141241 | | | | | | | | Standard Error | 0,050770391 | | | | | | | | Observations | 36

Related Essays

Statistics Essay 578 Words

578 words - 3 pages This paper will explain what statistics are. Statistics are used in so many ways, including business. This paper will thoroughly defining statistics, the types and levels of statistics, the role of statistics in a business and examples of how statistics may be used. The most common definition for statistics would be the collection of numerical data. Examples of numerical data could be the percentage of how many African-Americans passed

Statistics Essay 593 Words

593 words - 3 pages In a world ridden with endless problems and possibilities, it is statistics that is relied upon to find solutions to the problems and help determine what possibilities are truly feasible. Statistics may be best defined as the means by which data is gathered, analyzed, and interpreted to better understand a problem or situation. There are two types of data that can be analyzed in statistics. These are quantitative and qualitative data

Statistics Essay 2717 Words

2717 words - 11 pages Descriptive and Inferential Statistics ________________________________________ Statistics can be broken into two basic types. The first is known as descriptive statistics. This is a set of methods to describe data that we have collected. Ex. Of 350 randomly selected people in the town of Luserna, Italy, 280 people had the last name Nicolussi. An example of descriptive statistics is the following statement : "80% of these people have the

Statistics Essay 1100 Words

1100 words - 5 pages , observe and interpret information regarding this population. The purpose of this paper is to determine which methods of statistics are used as a measuring tool and what levels of measurements are used or could be used to improve the decision-making process for this organization. Statistics in the Workplace Many areas of the hospital facility use statistics in measurement. How do statistics affect this hospital healthcare facility in women