Statistics Test 1
Help!
|
|
||||
|---|---|---|---|---|---|
| observation | is an individual entity in a study
🗑
|
||||
| variable | characteristic that may differ among individuals.
🗑
|
||||
| Sample data | subset of a larger population.
🗑
|
||||
| Population data | collected when all individuals in a population are measured.
🗑
|
||||
| statistic | a summary measure of sample data.
🗑
|
||||
| parameter | summary measure of population data.
🗑
|
||||
| categorical variables | consist of group or category names that don’t necessarily have a logical ordering. Examples: eye color, country of residence.
🗑
|
||||
| ordinal variables | Categorical variables for which the categories have a logical ordering Examples: highest educational degree earned, tee shirt size (S, M, L, XL).
🗑
|
||||
| quantitative variables | consist of numerical values taken on each individual. Examples: height, number of siblings.
🗑
|
||||
| explanatory variable and response variable | In general, the value of the explanatory variable for an individual is thought to partially explain the value of the response variable for that individual.
🗑
|
||||
| relative frequency distribution | is a listing of all categories along with their relative frequencies (given as proportions or percentages, for example).
🗑
|
||||
| A frequency distribution for a categorical variable | is a listing of all categories along with their frequencies (counts).
🗑
|
||||
| Bar Graphs | useful for summarizing one or two categorical variables and particularly useful for making comparisons when there are two categorical variables.
🗑
|
||||
| Pie Charts: | useful for summarizing a single categorical variable if not too many categories.
🗑
|
||||
| extremes | high and low
🗑
|
||||
| quartiles | medians of lower and upper halves of the values
🗑
|
||||
| Outliers | a data point that is not consistent with the bulk of the data
🗑
|
||||
| Shape | clumped in middle or on one end (more later)
🗑
|
||||
| Spread | variability e.g. difference between two extremes or two quartiles.
🗑
|
||||
| Location | center or average. e.g. median
🗑
|
||||
| Histograms | similar to bar graphs, used for any number of data values.
🗑
|
||||
| Stem-and-leaf plots and dotplots | present all individual values, useful for small to moderate sized data sets.
🗑
|
||||
| Boxplot or box-and-whisker plot | useful summary for comparing two or more groups.
🗑
|
||||
| To illustrate shape | histograms and stem-and-leaf plots are best.
🗑
|
||||
| To illustrate location and spread, | any of the pictures work well
🗑
|
||||
| see individual values | use stem-and-leaf plots and dotplots.
🗑
|
||||
| To sort values | use stem-and-leaf plots.
🗑
|
||||
| To identify outliers | using the standard definition, use a boxplot.
🗑
|
||||
| compare groups, | use side-by-side boxplots.
🗑
|
||||
| What would outliers do to the mean | High outliers will increase the mean. Low outliers will decrease the mean.
🗑
|
||||
| The Influence of Outliers on the Mean and Median | Larger influence on mean than median
🗑
|
||||
| Range | high value – low value
🗑
|
||||
| Interquartile Range (IQR) = | upper quartile – lower quartile
🗑
|
||||
| Q1 = lower quartile | median of data values that are below the median
🗑
|
||||
| Q3 = upper quartile | median of data values that are above the median
🗑
|
||||
| Quartile Percentiles | Lower quartile = 25th percentile
Median = 50th percentile
Upper quartile = 75th percentile
🗑
|
||||
| The greater the distance a value is from the center, the fewer individuals have that value | “bell-shaped”. A special case is called a normal distribution or normal curve.
🗑
|
||||
| Standard deviation | measures variability by summarizing how far individual data values are from the mean.
🗑
|
||||
| Descriptive Statistics | numerical and graphical summaries to characterize a data set or describe a relationship.
🗑
|
||||
| Inferential Statistics: | using sample information to make conclusions about a broader range of individuals than just those observed.
🗑
|
||||
| Population | the entire group of units about which inferences are to be made.
🗑
|
||||
| Sample | the smaller group of units actually measured or surveyed.
🗑
|
||||
| Census: | every unit in the population is measured or surveyed.
🗑
|
||||
| Simple Random Sample | every conceivable group of units of the required size from the population has the same chance to be the selected sample.
🗑
|
||||
| Sample Survey | a subgroup of a large population questioned on set of topics. Special type of observational study.Less costly and less time than a census.
🗑
|
||||
| Advantages of a Sample Survey over a Census | -Sometimes a Census Isn’t Possible when measurements destroy units
-Speed especially if population is large
-Accuracy devote resources to getting accurate sample results
🗑
|
||||
| Selection bias | occurs if method for selecting participants produces sample that does not represent the population of interest.
🗑
|
||||
| Nonparticipation bias (nonresponse bias) | occurs when a representative sample is chosen but a subset cannot be contacted or doesn’t respond.
🗑
|
||||
| Biased response or response bias | occurs when participants respond differently from how they truly feel
🗑
|
||||
| Stratified Random Sampling | Divide population of units into groups (called strata) and take a simple random sample from each of the strata.
🗑
|
||||
| Cluster Sampling | Divide population of units into groups (called clusters), take a random sample of clusters and measure only those items in these clusters.
🗑
|
||||
| Systematic Sampling | Order the population of units in some way, select one of first k units at random and then every kth unit thereafter.
🗑
|
||||
| Multistage Sampling | Using a combination of the sampling methods, at various stages.
🗑
|
||||
| Random-Digit Dialing | Method approximates a simple random sample of all households in the United States that have telephones.
🗑
|
Review the information in the table. When you are ready to quiz yourself you can hide individual columns or the entire table. Then you can click on the empty cells to reveal the answer. Try to recall what will be displayed before clicking the empty cell.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
To hide a column, click on the column name.
To hide the entire table, click on the "Hide All" button.
You may also shuffle the rows of the table by clicking on the "Shuffle" button.
Or sort by any of the columns using the down arrow next to any column heading.
If you know all the data on any row, you can temporarily remove it by tapping the trash can to the right of the row.
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Created by:
talennna
Popular Music sets