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stats ch 1-3
| Question | Answer |
|---|---|
| is the science of collecting, organizing, summarizing, and analyzing information to draw conclusions or answer questions. is a numerical summary based on a sample. | Statistics |
| fact or proposition used to draw a conclusion or make a decision. | Data |
| The entire group of individuals to be studied. | population |
| a person or object that is a member of the population being studied. | individual |
| a subset of the population that is being studied. is a statistic. | sample |
| consist of organizing and summarizing data. describe data through numerical summaries, tables, and graphs. | Descriptive statistics |
| uses methods that take results from a sample, extends them to the population and measures the reliability of the result. | Inferential statistics |
| a numerical summary of a population. population mean. | parameter |
| are the characteristics of the individuals within the population. | Variables |
| allow for classification of individuals based on some attribute or characteristic. | Qualitative, or categorical, variables |
| provide numerical measures of individuals. its values can be added or subtracted and provide meaningful results. | Quantitative variables |
| is a quantitative variable that has either a finite number of possible values or a countable number of possible values. | discrete variable |
| means that the values result from counting, such as 0, 1, 2, 3 and so on. | countable |
| is a quantitative variable that has an infinite number of possible values that are not countable. | continuous variable |
| is a list of all individuals in a population along with certain characteristics of each individual. | census |
| is the process of using chance to select individuals from a population to be included in the sample. | Random sampling |
| every possible sample has an equally likely chance of occurring. | Simple Random Sampling |
| n | sample size |
| N | population size |
| is obtained by separating the population into nonoverlapping groups called strata and then obtaining a simple random sample from each stratum. | stratified sample |
| is obtained by selecting every kth individual from the population. | systematic sample |
| is obtained by selecting all individuals within a randomly selected collection or group of individuals. | cluster sample |
| is a sample in which the individuals are easily obtained and not based on randomness. | convenience sample |
| Data that is not organized | raw data |
| lists each category of data and the number of occurrences for each category of data. | frequency distribution |
| is the proportion (or percent) of observations within a category. | relative frequency |
| lists each category of data together with the relative frequency. | relative frequency distribution |
| is constructed by labeling each category of data on either the horizontal or vertical axis and the frequency or relative frequency of the category on the other axis. | bar graph |
| is a bar graph whose bars are drawn in decreasing order of frequency or relative frequency. | Pareto chart |
| is a circle divided into sectors. Each sector represents a category of data. (relative freq. times 360degrees) | pie chart |
| 1st step to quantitative you must know of it's. | discrete or continuous |
| with relatively few different values of the variable, then the categories of data (called classes) will be the observations (as in qualitative data). | descrete |
| but with many different values of the variable or if the data are continuous, then categories of data (classes) must be created using intervals of numbers. | discrete |
| is constructed by drawing rectangles for each class of data. The height of each rectangle is the frequency or relative frequency of the class. The width of each rectangle is the same and the rectangles touch each other. | histogram |
| are categories into which data are grouped. | Classes |
| is the smallest value within the class. | lower class limit |
| is the largest value within the class. | upper class limit |
| is the difference between consecutive lower-class limits. (works just the same as higher-class limits.) | class width |
| is another way to represent quantitative data graphically. use the digits to the left of the rightmost digit to form the stem. Each rightmost digit forms a leaf. | stem-and-leaf plot |
| the frequency of each value of the variable is evenly spread out across the values of the variable. | Uniform distribution |
| the highest frequency occurs in the middle and frequencies tail off to the left and right of the middle. | Bell-shaped distribution |
| the tail to the right of the peak is longer than the tail to the left of the peak. | Skewed right |
| the tail to the left of the peak is longer than the tail to the right of the peak. | Skewed left |
| is the sum of consecutive lower class limits divided by 2. | class midpoint |
| displays the aggregate frequency of the category. In other words, for discrete data, it displays the total number of observations less than or equal to the category. | cumulative frequency distribution |
| displays the proportion (or percentage) of observations less than or equal to the category for discrete data and the proportion (or percentage) of observations less than or equal to the upper class limit of a class for continuous data. | cumulative relative frequency distribution |
| is computed by adding all the values of the variable in the data set and dividing by the number of observations. | arithmetic mean |
| (pronounced “mew”), is computed using all the individuals in a population. | population arithmetic mean, µ |
| (pronounced “x-bar”), is computed using sample data. The sample mean is a statistic. | sample arithmetic mean, (x with a line on it) |
| is the value that lies in the middle of the data when arranged in ascending order. represents M. | median |
| is the most frequent observation of the variable that occurs in the data set. | mode |
| ____and_____need numerical, but_____can use numerical and categorical. | mean and median, mode |
| is the difference between the largest and the smallest data value. | range, R |
| is the square root of the sum of squared deviations about the population mean divided by the number of observations in the population, N. That is, it is the square root of the mean of the squared deviations about the population mean. | population standard deviation |
| is the square root of the sum of squared deviations about the sample mean divided by n – 1, where n is the sample size. | sample standard deviation, s |
| is the square of the standard deviation. | variance |
| 𝜎 squared | population variance |
| 𝑠 squared | sample variance |
| 68% lie within 1 STDEV of the mean. 𝜇−1𝜎 and 𝜇+1𝜎 95% lie within 2 STDEV of the mean. 𝜇−2𝜎 and 𝜇+2𝜎 99.7% lie within 3 STDEV of the mean. 𝜇−3𝜎 and 𝜇+3𝜎 | The Empirical Rule |
| of a variable is found by multiplying each value of the variable by its corresponding weight, adding these products, and dividing this sum by the sum of the weights. | weighted mean, "x var" with bottom corner "w." |
| represents the distance that a data value is from the mean in terms of the number of standard deviations. We find it by subtracting the mean from the data value and dividing this result by the standard deviation. | z-score |
| denoted 𝑃 "with bottom corner k", of a set of data is a value such that k percent of the observations are less than or equal to the value. | kth percentile |
| divide data sets into fourths, or four equal parts. | Quartiles |
| denoted 𝑄1, divides the bottom 25% of the data from the top 75%. | first quartile |
| Q2, divides the bottom 50% of the data from the top 50%; it is equivalent to the 50th percentile or the median. | second quartile |
| 𝑄3, divides the bottom 75% of the data from the top 25%; it is equivalent to the 75th percentile. | third quartile |
| is the range of the middle 50% of the observations in a data set. | interquartile range, IQR |
| Shape of Distribution and Measure of Central Tendency. Symmetric, Mean | standard deviation |
| Shape of Distribution and Measure of Central Tendency. Skewed left or skewed right, Median | interquartile range |
| Extreme observations | outliers |
| serve as cutoff points for determining outliers. | Fences |
| Minimum, Q1, M, Q3, Maximum | Five-Number Summary |
| know how to draw a box plot | know how to draw a box plot |