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Prob/Stat Ch. 1
1.1, 1.2, 1.3, 14.1, 14.2
Term | Definition |
---|---|
Statistics | Science of conducting studies to collect, organize, summarize, analyze, and draw conclusions from data |
How is statistics used in everyday life? 4 examples. | 1.Used in fields of human endeavor - sports, public health, and education. 2.Analyze results of surveys. 3.Tool in science research to make decisions based on controlled experiments. 4.Operations research, quality control estimation, and predictions. |
3 reasons to study statistics | 1.understand statistical studies 2.conduct research, design experiments,make predictions, and communicate results 3.become better consumers |
Descriptive Statistics | consists of collection, organization, summarization, and presentation of data |
Inferential Statistics | generalizing from samples to populations, performing estimations and hypothesis tests, determining relationships among variables, and making predictions |
Qualitative Variables | distinct categories (characteristic or attribute) data is NOT numbers |
Quantitative Variables | numerical and can be ordered or ranked (age, height, weight, body temp) 1.)Discrete - assume values that can be counted 2.)Continuous - can assume an infinite number of values between any two specific values. |
Boundaries | Ex: 4 = 3.5-4.5 |
Nominal Measurement | no order or ranking can be imposed on the data (gender, zip code, political party, marital status, eye color, religious affiliation, nationality) |
Ordinal Measurement | can be ranked, but precise differences between the ranks do not exist (speakers: poor, fair, good) (ranking: 1st, 2nd, 3rd) (person's build: S, M, L, XL) |
Interval Measurement | ranks data and precise differences between units of measure do exist, no zero (IQ Tests, temperature, SAT scores) |
Ratio Measurement | possesses all characteristics of interval measurement and a true zero exists (height, weight, area, number of calls received, number of pounds lifted, time, salary, age) |
Two purposes of data collection | 1.)Descsribe situations or events 2.)Help people make better decisions before acting |
Three ways to collect data | 1.)Surveys 2.)Surveying Records 3.)Direct Observation |
Telephone Survey: A&D | A:less costly, people can be more candid D:not all people can be surveyed, may not be home, unlisted and cell phones, tone of interviewer may turn off person being called |
Variable | A character or attribute that can assume different values |
Data | the values that variables assume |
Random Variables | variables whose values are determined by chance |
Data set | A collection of data values |
Data value(Datum) | Each value of the data set |
Probability | The chance of an event occurring |
Population | Consists of all subjects that are being studied |
Sample | A group of subjects selected from a population |
Hypothesis Testing | A decision making process for evaluating claims about a population based on information from samples |
Mailed Questionnaire: A&D | A:cover wider geographic area, less expensive to conduct, respondents can remain anonymous D:low number of responses, inappropriate answers on questions, may be hard to understand |
Personal Interview: A&D | A:obtain in-depth responses D:interviewers need to be trained, more costly, interviewer may be biased, may not be good sampling of people interviewed |
Random Sampling | every member of the population must have an equal chance of being selected; random numbers generated by computer, etc. |
Systematic Sampling | sample obtained by numbering each element in the population and then selecting every nth number from the population to be included in the sample. done after first number is selected at random |