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ap stats vocab 1
Term | Definition |
---|---|
variable | holds information about the same characteristic for many subjects |
categorical variable | where the data collected places the individuals in various categories or groups |
quantitative variable | where the data collected is numerical and it makes sense to use it for numerical operations |
frequency table | lists the categories for a categorical variable and displays the counts for each category |
relative frequency table | lists the categories for a categorical variable and displays the percenatges for each category |
distribution | describes how a quantitative variable behaves. generally include shape, center, spread, & unusual features |
bar chart | a display for categorical data that uses bar height to represent counts or percentages for each category |
histogram | a display for quantitative data that uses adjacent bars to represent counts or percentages of values falling in each interval |
stem & leaf (stemplot) | a display for quantitative data that uses place values to represent the distributions |
dot plot | a display for either kind of data that uses a dot to represent each individual in the data set |
measures of center | mean for distributions that are symmetric, median for all other distribution shapes |
measures of spread | standard deviation for distributions that are symmetric, IQ for all other distribution shapes |
uniform distribution | a distribution whose shape is evenly distributed throughout the values it takes |
symmetric distribution | a distribution whose shape is unimodal and each side is roughly a mirror image of the other |
left skewed distribution | a distribution that has a concentration of data on the upper end and the tail on the left |
right skewed distribution | a distribution with a concentration of data on the lower distribution end and the tail on the right |
outliers | values that fall outside the overall pattern of the data |
mean | the average of the data values |
median | the value in the center of an ordered data set |
range | the maximum data value minus the minimum data value |
first quartile | the value where 25 % of the data fall below it in an ordered list |
third quartile | the value where 75% of the data falls below it in an ordered list |
interquartile range (IQR) | the third quartile minus the first quartile |
percentile | the place in the data where a certain percentage of the data falls below that value |
5 number summary | includes the minimum, first quartile, median, third quartile, & the maximum |
modified boxplot | a display for quantitative data that graphs the five-number summary on an axis and shows outliers of the exist |
variance | the standard deviation squared, it is a measure of spread |
advantage of stemplot | retains the actual data values from the data set |
advantage of histogram | easy to see shape of distribution & good for large data sets |
resistant | values that are not strongly affected by extreme values, the median is more resistant that the mean. The standard deviation is most strongly affected by extreme values |
explanatory variable | attempts to explain the observed outcomes in a statistical study (known as independent variable) |
response variable | measures the outcome of a statistical study (known as dependent variable) |
sample | a part of the population used to gather information about the entire population |
population | the entire group of individuals that we want information about |
qualitative data | data that can be arranged categorically based on the attributes and properties of a thing or a phenomenon (known as categorical data) |
numerical data | values that can be measured and put into a logical order |
marginal distribution | totals for the probabilities. shown in the margins of the table (B/C) |
conditional distribution | probability distribution for a sub-population (A/B) |
independence | same percentage between marginal and conditional distribution |