Statistics – the science of planning studies and experiments, obtaining data, and then organizing, summarizing, presenting, analyzing, interpreting, and drawing conclusions based on the data. Population – the collection of all elements to be studied. Census – a collection of data from every member of the population Sample – a subset of members selected from a population
Vocabulary 1 – Chapter 1 Section 2
Statistical Significance – an arbitrary limit where an observed difference is reasonably assumed to be due to some factor other than pure chance. Practical significance – an arbitrary limit where an observed difference is of some practical use in the real world. Vocabulary 1 – Chapter 1 Section 3
Parameter – a numerical measurement of a population characteristic. Statistic – a numerical measurement of a sample characteristic. Quantitative Data – data that consists of numbers representing counts of measurements. Categorical Data – data that can be separated into different categories that are distinguished by some nonnumeric characteristic.
Discrete Data – data that has a finite number or countable number of possible values. Continuous Data – data that has an infinite number of possible values, with no gaps in the possible values. Nominal Level of Measurement – data that are qualitative only. Ordinal Level of Measurement – data that can be ordered, but computational differences are meaningless. Interval Level of Measurement – data that are ordinal level, and also having meaningful computational differences, but having no significant zero value.
Ratio Level of Measurement – data that are interval level, and also having meaningful computational differences, and having a significant zero value. Vocabulary 1 – Chapter 1 Section 4
Voluntary Response Sampling – a style of sampling that incorporates non probability sampling methods in its research. Correlation – the degree to which two or more attributes or measurements on the same group of elements show a tendency to vary together.
Causality – the principle that nothing can happen without being caused. Order of Questions – sometimes survey questions are unintentionally loaded by factors of the items being considered. Nonresponse – occurs when someone either refuses to respond to a survey question or is unavailable. Missing Data – occurs when no data value is stored for the variable in an observation. Vocabulary 1 – Chapter 1 Section 5
Observational Study – observe and gather data without attempting to modify the subjects. Experiment – apply some treatment and then observe the effects of the treatment on the subjects. Simple Random Sample – a sample of n subjects that is selected in a way that makes every possible sample of size n is equally likely. Random Sample – a sample in which each individual member of a population is equally likely to be chosen. Probability Sample – a sample in which each individual member of a population has a known chance of being chosen.
Systematic Sample – a sample selected by choosing a starting point in the list of subjects and then selecting every kth subject from that point on. Convenience Sample – a sample selected by choosing subjects that are most easily accessed. Stratified Sample – a sample selected by dividing the population into at least two subgroups and then choosing subjects from each subgroup. Cluster Sample – a sample selected by dividing the population into at least two subgroups, randomly selecting subgroups, and then choosing all subjects from the selected subgroups. Sampling Error – error in a statistical analysis arising from the unrepresentativeness of the sample taken.