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Group Members: Charlie, Tyler, Renzheng Model of the Big Bang The Big Idea Analyze data by using graphs and numerical summaries Use graphs to display categorical or quantitative data Describe the overall pattern by interpreting shape, center, spread, and outliers (SOCS) Choose a which center and summary best fits the data. (mean and deviation or five-number summary) Determine the effect of a linear transformation on center and spread Vocabulary You Need to Know Individuals – are the objects described by the data. Can be people or things Variables – are any characteristics of an individual Categorical variables - places an individuals into groups or categories Quantitative variables – takes numerical values like 2 or 4.5 Distribution – of a variable tells us what values the variable takes and how often it takes these values Key Topics Covered in this Chapter Graph categorical data on pie charts and bar graphs. Graph quantitative data on stemplots and histograms, Ogive or relative cumulative frequency graphs and timeplots are quantitative Describe Shape: symmetric or skewed, unimodal or no modes Describe Center: Mean or Medium. They are the same in symmetric but in a skewed, the mean is farther out than the median near the tail Describe Spread: range, quartiles, five number summary, standard deviation Outliers: Median and quartiles are resistant. Mean and Std deviations arnt Formulas You Should Know Mean Variance Standard Deviation Outliers smaller than Q1 – (1.5 *IQR) or larger than Q3 – (1.5*IQR) Linear transformation xnew = a + bx (a shifts values up or down, b changes the size) Five number summary (min, Q1, medium, Q3, max) Range = maximum – minimum Calculator Key Strokes Enter data into L1 and L2 then press 1-var stat under calculations. This will find the mean and standard deviations. Remember the difference between (s) sample and (σ) population Helpful Hints Use back to back stemplots and side by side boxplots are used to compare quantitative distributions Use mean and standard deviation for symmetric and Normal distributions and the five number summary for skewed distributions The sum of all deviations from their mean will always be 0. s = 0 only when all observations have the same value The number n – 1 is called the degrees of freedom of the variance or std. deviation Average value refers to the mean and typical value to the medium Histograms should always have bins of the same size and the bars touch each other Example Problem(s) -799, 0, 4, 32, 54 ,93, 354, 354, 1534, 3942, 4032, 5030 a) Find the Five number summary b) Find any outliers c) Find the mean and standard deviation d) Make a boxplot and a histogram e) Describe SOCS a) (-799, 43, 86, 2738, 5030) b) None c) Mean = 1219.1666 std dev. = 1965.9759 d) e) Skewed, no outliers, medium, quartiles