Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
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
Statistics
Chapter 3 & 4
| Question | Answer |
|---|---|
| measures of central tendency such as ________________________________ summarize a distribution of scores by describing the most common, the middle score, or the average score of the distribution | mode, median, and mean |
| central purpose of descriptive statistics is to __________________ data | summarize or reduce |
| always the exact center of a distribution of scores | mode |
| median can be found for _______________ data, but generally it more appropriate for ______________ data. | interval ratio; ordinal |
| ______________identifies a point below which a specific percentage of cases fall | percentile |
| the 5th decile, is equal to the ________ percentile | 50th |
| D1 or the first decile is the point below which ______________ of the cases fall | 10% |
| If you scored higher than the 3rd quartile (Q3) then you made __________________________ | above 75% of the scores |
| most commonly used measure of central tendency | mean (x bar) |
| formula for mean (x bar)= | the sum of (xi) / N |
| three characteristics of the mean: | 1. the mean balances out all scores (mean is pt around which all scores cancel out); 2. mean minimizes variation of scores (least squares principle); 3. mean affected by all scores and can be misleading if distribution has extreme outliers |
| what does least square principle say? | mean is pt around which variation of score is minimized; if difference b/t scores and mean are squared and then added, the resultant sum will be less than the sum of the squared differences b/t the scores and any other point in the distribution |
| This principle underlies the fact that the mean is closer to all of the scores than the other measures of central tendency | least squares principle |
| distributions with outliers have a ___________: | skew |
| if you have some extremely high outliers, what will happen to the distribution curve? | it will skew to the right (+) = (mean>median) |
| when mean > median, what would you expect your distribution curve to look like? | skewed to the right (+ skew) |
| if you have some extremely low outliers, what will happen to the distribution curve? | it will skew to the L (-) = mean< median |
| if mean < median, what would you expect your distribution curve to look like? | skewed to the left (- skew) |
| the mean will be pulled _______________ of the outlying scores relative to the median | in the direction |
| the greater the skew, the ______________ the difference between the 2 measures of central tendency (mean & median) | greater |
| the mean and median will have the same value only in distributions that are ________________- | symmetrical |
| the mode is the most ___________________ and is used most appropriately with _____________________variables | common value; nominal-level |
| _____________ describe the variety, diversity, or heterogeneity of a distribution of scores; describes the variability of data (variants.) | measures of dispersion |
| measure of dispersion can reveal substantial differences between distributions even when _____________________ are the same | measures of central tendency |
| range: | distance between highest and lowest scores in distribution (high score-low score) |
| the greater the value of a range the greater the _______________ in the distribution | dispersion |
| limitations to range | range might exaggerate the amount of dispersion for most of scores in distribution |
| IQR: | the distance from the third to 1st quartile; a kind of range that acoids some of the problems associated with range outliers by considering only the middle 50% of the cases in distribution |
| three traits a good measure of dispersion should include: | should use all the scores in the dist; should describe the average or typical deviation of the scores; increase in value as the scores become more diverse |
| the sum of squared deviations will _______________ with sample size | increase |
| using the median, range and IQR depicts both the _______________ and _____________________- | central tendency; variability |
| horizontal line in the middle of the IQR box represents : | median |
| scores that are beyond 3 times the height of the IQR box in either direction are termed: | extreme outliers (outliers are outside of 1.5 height of box or outside the whiskers) |
| the standard deviation is ____________ for more diverse distributions and ______________ for less diverse distributions | higher; lower |
| sigma of x-sub-I = | the sum of all data points |
| t/f data that has a mean of 30 and a range of zero means there is littler variance | false - no variance |
| if you take all data points in a sample and find the difference between the mean and the sum, the answer will always be? | 0 |
| the sum of x sub i - x bar = | 0 |
| limitations to mean: | outliers (extreme values) skew the mean |
Created by:
aereal