Fichas
215 U1
Fichas del conjunto (40)
- 1StatisticsThe science of collecting, analyzing, presenting, and interpreting data, as well as of making decisions based on such analyses. In common usage, statistics refers to numerical facts.
- 2Descriptive StatisticsConsists on methods for organizing, displaying, and describing data using tables, graphs, and summary measures.
- 3Inferential StatisticsConsists of methods that use sample results to help make decisions or predictions about a population.
- 4Population or Target PopulationA population consists of all elements-indiviuals, items, or objects- whose characteristics are being studied. The population that is being studied is also called the target population.
- 5SampleA portion of the population selected for study.
- 6Census and Sample SurveyA survey that includes every member of the population is called a census. The technique of collecting information from a portion of the population is called a sample survey.
- 7Representative SampleA sample that represents the characteristics of the population as closely as possible.
- 8Random SampleA sample drawn in such a way that each element of the population has a chance of being selected is called a random sample. If all samples of the same size selected from a population have the same chance of being selected, we call it simple random sampling (simple random sample).
- 9Element or MemberAn element or member of a sample or population is a specific subject or object (person, firm, item, state, or country) about which the information is collected.
- 10VariableA characteristic under study that assumes different values for different elements. In contrast to a variable, the value of a constant is fixed.
- 11Observation or MeasurementThe value of a variable for an element.
- 12Data SetA collection of observations on one or more variables.
- 13Quantitative VariableA variable that can be measured numerically. The data collected on a quantitative variable are called quantitative data.
- 14Discrete VariableA variable whose values are countable, andcan assume only certain values with no intermediate values.
- 15Continuous VariableA variable that can assume any numerical value over a certain interval or intervals is called a continuous variable.
- 16Qualitative or Categorical VariableA variable that cannot assume a numerical value but can be classified into two or more nonnumeric categories. The data collected on such a variable are called qualitative data.
- 17Cross-Section DataData collected on different elements at the same point in time or for the same period of time.
- 18Time-Series DataData collected on the same element for the same variable at different points in time or for different periods of time.
- 19Internal sourcesSources of data that are inside the organization conducting the study which make needed data available.
- 20External sourcesSources of data that are outside the organization from which data is available.
- 21Raw DataData recorded in the sequence in which they are collected and before they are processed or ranked.
- 22Frequency Distribution of a Qualitative VariableA table that lists all the categories or classes and the number of values that belong to each of these categories or classes.
- 23Bar GraphA graph made of bars whose heights represent the frequencies of respective categories.
- 24Pie ChartA circle divided into portions that represent the relative frequencies or percentages of a population or a sample belonging to different categories.
- 25Frequency Distribution for Quantitative DataA frequency distribution for quantitative data lists all the classes and the number of values that belong to each class. Data presented in the form of a frequency distribution are called grouped data.
- 26Class BoundaryA class boundary is given by the midpoint of the upper limit of one class and the lower limit of the next class.
- 27HistogramA histogram is a graph in which classes are marked on the horizontal axis and the frequencies, relative frequencies, or percentages are marked on the vertical axis. The frequencies, relative frequencies, or percentages are represented by the heights of the bars. In a histogram, the bars are drawn adjacent to each other.
- 28PolygonA graph formed by joining the midpoints of the tops of successive bars in a histogram with straight lines.
- 29Cumulative Frequency DistributionA cumulative frequency distribution gives the total number of values that fall below the upper boundary of each class.
- 30OgiveA curve drawn for the cumulative frequency distribution by joining with straight lines the dots marked above the upper boundaries of classes at heights equal to the cumulative frequencies of respective classes.
- 31Stem-and-Leaf DisplayIn a stem-and-leaf display of quantitative data, each value is divided into two portions—a stem and a leaf. The leaves for each stem are shown separately in a display.
- 32Outliers or Extreme ValuesValues that are very small or very large relative to the majority of the values in a data set.
- 33MeanThe arithmetic average of the scores in a distribution.
- 34MedianThe median is the value of the middle term in a data set that has been ranked in increasing order.
- 35ModeThe mode is the value that occurs with the highest frequency in a data set.
- 36Population Parameter (or simply Parameter)A numerical measure such as the mean, median, mode, range, variance, or standard deviation calculated for a population data set (
- 37Sample Statistic (or simply Statistic)A summary measure calculated for a sample data set (x with top bar, and s)
- 38Chebyshev's TheoremFor any number
- 39QuartilesThree summary measures that divide a ranked data set into four equal parts. The second quartile is the same as the median of a data set. The first quartile is the value of the middle term among the observations that are less than the median, and the third quartile is the value of the middle term among the observations that are greater than the median.
- 40Box-and-Whisker PlotA plot that shows the center, spread, and skewness of a data set. It is constructed by drawing a box and two whiskers that use the median, the first quartile, the third quartile, and the smallest and the largest values in the data set between the lower and the upper inner fences.