Ch 1 Stats
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40 terms
Terms | Definitions |
|---|---|
 Data | Observations (such as measurements, genders, survey responses) that have been collected. |
| Statistics | A collection of methods for planning studies and experiments, obtaining data, and then organizing, summarizing, presenting, analyzing, interpreting, and drawing conclusions based on the data. |
| Population | The complete collection of all elements (scores, people, measurements, and so on) to be studied. The collection is complete in the sense that it includes all subjects to be studied. |
| Census | Collection of data from every member of the population. |
| Sample | A sub collection of members selected from a population. |
| Parameter | Numerical measurement describing some characteristic of a population. |
| Statistic | A numerical measurement describing some characteristic of a sample. |
| Quantitative data | Consists of numbers representing counts or measurements. Describes a characteristic |
| Qualitative data | Can be separated into different categories that are distinguished by some nonnumerical characteristic. |
| Discrete data | When the number of possible values is either a finite number or a "countable" number. (That is, the number of possible values is 0 or 1 or 2 and so on.) |
| Continuous (numerical) data | From infinitely many possible values that correspond to some continuous scale that covers a range of values without gaps, interruptions or jumps. |
| Ordinal level of measurement | Catagories are ordered but differences are meaningless: 5 compact, 20 mid-size, 40 full-size cars |
| Interval level of measurement | Differences are meaningful but there is no natural "0" starting point: Temperatures: 5, 10, 76 |
| Ratio level of measurement | There is a natural "0" starting point and ratios are meaningful: Student commuting Distance: 5mi, 20mi, 40mi |
| Voluntary response sample/Self-selected sample | One is in which the respondents themselves decided whether to be included. |
| Observational study | We observe and measure specific characteristics, but we don't attempt to modify the subjects being studied. |
| Experiment | We apply some treatment and then proceed to observe its effects on the subjects. |
| Experimental units. | Subjects in experiments are called? |
| Cross-sectional study | Data are observed, measured, and collected at one point in time. |
| Retrospective study | Data are collected from the past by going back in time (through examination of records, interviews, and so on). |
| Case-control | Data are collected from the past by going back in time (through examination of records, interviews, and so on). |
| Prospective study/Longitudinal/Cohort | Data are collected in the future from groups sharing common factors (called cohorts). |
| Confounding | Occurs in an experiment when you are not able to distinguish among the effects of different factors. |
| Random sample | Members from the population are selected in such a way that each individual member has an equal chance of being selected. |
| Simple random sample | N subjects is selected in such a way that every possible sample of the same size has the same chance of being chosen. |
| Probability sample | Involves selecting members from a population in such a way that each member has a known (but not necessarily the same) chance of being selected. |
| Systematic sampling | Select a starting point and select every kth person i.e. every 50th person |
| Convenience sampling | We simply use results that are very easy to get. |
| Cluster sampling | Divide the pop. into sections and then randomly select certain sections and use all of the people in that section |
| Sampling error | The difference between a sample result and the true population result; such an error results from chance sample fluctuations. |
| Nonsampling error | Occurs when the sample data are incorrectly collected, recorded, or analyzed (such as by selecting a biased sample, using a defective measure instrument, or copying the data incorrectly). |
| Box Plot | Min, Q1, Median, Q3, Max |
| Relative Frequency | Part/Total |
| Usual Data Value | Between x= -2s or x= +2s |
| Unusual Data Value | Below x= -2s or above x= +2s |
| Which two data values are the only two to get rounded? | Z-Scores and Median |
| Calculate class width | Find the Range: Biggest # - Smallest # / The amount of classes wanted Round up |
| To find the mean, Variance, and SD on the Freq. Table | Input the Freq. x Mid pnt. column and use the data from the calculator |
| Stratified Sampling | Subdivide the population into groups that share a characteristic such as gender then draw a sample from each subgroup |
| Nominal Measurement | Categories only with no ordering scheme: Student states: 5 Cali, 10 Texas |
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