# Shared Flashcard Set

## Details

Statistics - Mind on Statistics - Utts & Heckard
Mind on Statistics chapter 2 definitions Utts & Heckard
73
Mathematics
01/18/2010

Term
 Population
Definition
 Is a collection of all individuals about which information is desired. ?The individuals? are usually people but could also be schools, cities, pet dogs, agricultural fields, and so on.
Term
 Random Sample
Definition
 Is a subset of the population selected that every individual has a specified probability of being part of the sample.
Term
 Sample Survey:
Definition
 The investigators gather opinions or other information from each individual included in the sample.
Term
 Margin of Error:
Definition
 Fir a properly conducted survey is a number that is added to and subtracted form the sample information to produce an interval that is 95% certain to contain the truth about the population. In the most common types of sample surveys, the margin of error is approximately equal to 1 divided by the square root of the number of individuals in the sample.
Term
 Nonresponse Bias:
Definition
 Can occur when many people who are selected for the sample either do not respond at all or do not respond to some of the key survey questions.
Term
 Self-Selected Sample:
Definition
 In most case, this kind of sample tells you nothing about the larger populations at all; it tells you only about those who responded. (Used by Magazines, television stations, and Internet websites)
Term
 Volunteer Sample
Definition
 In most case, this kind of sample tells you nothing about the larger populations at all; it tells you only about those who responded. (Used by Magazines, television stations, and Internet websites)
Term
 Observational Study:
Definition
 Is one in which participants are merely observed and measured.
Term
 Variable:
Definition
 Is a characteristic that differs from one individual to the next. It may be numerical, such as blood pressure, or it may be categorical, such as whether or not someone attends church regularly.
Term
 Confounding Variable:
Definition
 Is a variable that is not the main concern of the study buy may be partially responsible for the observed results.
Term
 Raw Data pg. 13
Definition
 is a term used for numbers and category labels that have been collected but have not yet been processed in anyway.
Term
 Variable pg. 14, 15
Definition
 is a characteristic that can differ from one individual to the next.
Term
 Observational unit pg. 14 ?
Definition
 is a single individual who participates in a study.
Term
 Observation pg. 14 ?
Definition
 is an individual study.
Term
 Sample size pg. 14 ?
Definition
 for a study is the total number of Observational unit.
Term
 Dataset pg. 14 ?
Definition
 is the complete set of raw data, for all Observational units and variables, in a survey or experiment.
Term
 Sample data pg. 14 ?
Definition
 measurements are taken from a subset of a population.
Term
 Population data pg. 14 ?
Definition
 all individuals in a population are measured.
Term
 Statistic pg. 15 ?
Definition
 a summary measure computed from sample data.
Term
 Parameter pg. 15 ?
Definition
 a summary measure for an entire population.
Term
 Descriptive statistics pg. 15 ?
Definition
 a summary numbers for either a population or a sample.
Term
 Categorical Variable pg. 15, 17 ?
Definition
 consists of group or category names that don?t necessarily have any logical ordering.
Term
 Ordinal Variable pg. 16, 17 ?
Definition
 may be used to describe the data when a categorical variable has ordered category.
Term
 Quantitative Variable pg. 16, 17 ?
Definition
 is recorded as numerical value and the data are entire measurements or courts taken on each individual.
Term
 Measurement Variable & Numerical Variable pg. 16 ?
Definition
 are synonyms for quantitative variable
Term
 Continuous Variable pg. 16 ?
Definition
 can also be used for quantitative data when every value within some interval is a result.
Term
 Questions for Variable types pg. 17 & 18 ?
Definition
 are asking the right questions like, is it an One Categorical Variable, Two Categorical Variable, One Quantitative Variable, One Categorical Variable and One Quantitative Variable, and lastly Two Quantitative Variable.
Term
 Explanatory Variable pg. 18 - 21
Definition
 Any variable that explains the response variable. Often called an independent variable or predictor variable.     for an individual is thought to partially explain the value of the Response Variable pg. 18, 21 for that individual.
Term
 Frequency-
Definition
 a synonym for the count of how many observations fall into a category
Term
 Relative frequency-
Definition
 the count in a category relative to the total count over all categories
Term
 Frequency distribution-
Definition
 for a categorical variable is a listing of all categories along with their frequencies
Term
 Relative frequency distribution-
Definition
 is a listing of all categories along with their relative frequencies (given as proportions or percentages)
Term
 Outcome variable-
Definition
 also called response variable used in summarizing two categorical variables
Term
 Pie chart-
Definition
 useful for summarizing a single categorical variable if there are not too many categories
Term
 Bar graph-
Definition
 useful for summarizing one or two categorical variables and are particularly useful for making comparisons when there are two categorical variables
Term
 dot plot -
Definition
 chart consisting of group of data points plotted on a simple scale. Dot plots are used for continuous, quantitative, unvaried data
Term
 Five number summary -
Definition
 consists of the median, the quartiles, and the extremes
Term
 Distribution -
Definition
 the over all pattern of how often the possible values occur in a quantitative variable.
Term
 Location -
Definition
 the center of the distribution values
Term
Definition
 the variability among individual measurements
Term
 Shape -
Definition
 how the values are distributed
Term
 Outlier -
Definition
 data not consistent with the bulk of the data
Term
 Median -
Definition
 the middle value
Term
 Mean -
Definition
 the average of all of the values
Term
 Variability -
Definition
Term
 Histogram -
Definition
 similar to bar graphs, not as informative for small samples, used for quantitative data. Shows how many values are in various intervals of the data
Term
 Stem-and-Leaf plot -
Definition
 created much like a histogram, except every individual data value is shown. Quick way to summarize or order data from lowest to highest
Term
 Box plot -
Definition
 simple way to show five number summaries, uses the extremes, quartiles and the median
Term
 Symmetric -
Definition
 similar on both sides of the center
Term
 Skewed -
Definition
 values are more spread on one side of the center than the other
Term
 Skewed right -
Definition
 the higher values are more spread than the lower values
Term
 Skewed left -
Definition
 the lower values are more spread than the higher values
Term
 Bell-shaped -
Definition
 another symmetric shape
Term
 Mode -
Definition
 the most frequent value
Term
 Unimodal -
Definition
 a single prominent peak in a histogram
Term
 Bimodal -
Definition
 if there are two prominent peaks in a histogram
Term
 Range-
Definition
 high value - low value
Term
 Interquartile range (IQR)-
Definition
 upper quartile ? lower quartile. The notation IQR is often used to represent the interquartile range.
Term
 Standard deviation-
Definition
 The standard deviation gives an idea of how close the entire set of data is to the average value. Data sets with a small standard deviation have tightly grouped, precise data. Data sets with large standard deviations have data spread out over a wide range of values.
Term
 Lower quartile-
Definition
 is the median of the data values that are located below the median
Term
 Upper quartile-
Definition
 is the median of the data values that are located above the median
Term
 Quartiles-
Definition
 the lower and upper values are called quartiles because along with the median and the extremes, they divide the ordered data into quarters
Term
 Resistant statistic-
Definition
 a numerical summary of the data that is resistant to the influence of outliers
Term
 Percentile-
Definition
 in general the kth percentile is a number that has k% of the data values at or below it and (100 ? k)% of the data values at or above it
Term
 Reasons for outliers-
Definition
 the outlier is a legitimate data value and represents natural variability for the group and variables measured. Values may not be discarded in this case. A mistake was made while taking a measurement or entering it into the computer. If this case be verified/ the values should be discarded or corrected. The individual in question belongs to a different group than the bulk of individuals measured. Values may be discarded if a summary is desired and reported for the majority group only.
Term
 Bell shaped curve-
Definition
 numerical values that follow this distribution of measurement is so common it is also called a normal distribution or normal curve
Term
 Variance-
Definition
 the squared value of the standard deviation and is represented by s2
Term
 Population mean-
Definition
 represented by the greek letter U or ?mu?
Term
 Population standard deviation-
Definition
 is represented by the greek letter o or ?sigma?
Term
 Empirical rule-
Definition
 for any bell shaped curve approximately 68% of the values fall within 1 standard deviation of the mean in either direction, 95% of the values fall within 2 standard deviations of the mean in either direction, and 99.7% of the values fall within 3 standard deviations of the mean in either direction
Term
 Standardized score-
Definition
 a useful measure of the relative value of any observation in a data set
Term
 z-score- see standardized score
Definition
 a measure that quantifies the distance a data point is from the mean of a data set.
Term
 Responce Variable
Definition
 The outcome of a study.  A variable you would be interested in predicting or forecasting. Often called a dependent variable or predicted variable.
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