Statitics Terms
Terms
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- Ogive
- A cumulative line graph best used to display the total at any given time
- Deviation
- The distance of the measurements away from the mean
- Two standard deviations
- Approximately 95% of the measurement
- Nominal
- A scale that measures data by name only (religious affiliation, etc.)
- Interval
- A scale that measures by using equal intervals (tempreture)
- Variance
- The sum of the squared deviations of n measurements from their mean divided by (n-1)
- Negatively skewed
- Tilts towards the right
- Independent event
- outcomes not affected by other outcomes (successive coin flips)
- Modal Value
- The most frequently reported category
- Standard deviation
- The positive square root of the variance
- Mean Value
- The average of all vaues
- Positively skewed
- Tilts towards the left
- Multipication Rule
- For the probability of 2 or more independent events all occurring multiply their probabilities
- Ordinal
- A scale that measures by rank order only (military rank, etc.)
- Stem and Leaf
- Shows the range of data, where the data are concentrated, and outliers.
- Median Value
- Half the results are above and half below
- Addition rule
- For mutually exclusive events, find the pr. of at least one of them occuring is obtained by adding their probabilities
- Ratio
- A scale that inclues a 0 measurement at which point the measured characteristic vanishes (yrs. of education, income)
- Bimodal cuves
- A curve with two high points
- Qualitative date
- numerical information about categories that vary significantly in kind (gender, religious affiliation, etc.)
- One standard deviation
- Approximately 68% of the measurement
- Dependent events
- Outcomes effected by other outcomes (removing cards from a deck)
- Relative frequency theory of probability
- If an experiment is repeated a large number of times and an outcome occurs a percentage of that time, that percentage is close to the prob. of that outcome
- Relative frequency histogram
- Compares each class interval to the total number of items
- Probability
- The chance of a particular outcome occurring is determined by the ratio of favorable outcomes (successes) to the total number of outcomes
- Frequency Histogram
- tells how many items are in each numerical category
- Box plots
- Displays a number of values of a distribution of numbers
- Quantitative data
- Can be measured in amounts (age, salary)
- Scatterplot
- displays information about the relationship involving two different phenomena such as days studied and score earned
- Frequency distributions
- used smooth curve to connect the points and is plotted on two axes. The horzional (x) are the values of a variable while the vertical (y) measures the frequency or how many times a particular value occurs)
- Three standard deviations
- Approximately all of the measurements
- Range
- The difference between the largest and smallest values