Review of basic statistics Chapter 14 and 15 part I Bold and Italic typed is my prediction that it will appear on the exam A Terminology Population entire set of all elements that share common characteristics Sample subset of population Parameter summary that describe the characteristics of a population e g Statistics summary that describe characteristics of a sample Application question testing the difference between parameter and statistics Goal of marketing research learn about the population through collecting samples which can help describe and make inference about the population How do we learn about the population B Types and definitions of statistics Descriptive statistics summarize data e g s x bar Expression graphical e g histogram and numerical mode median mean Inferential statistics drawing conclusions about populations based upon statistics Population distribution frequency distribution of all possible observation in the population e g It is unknown Sample distribution frequency distribution of observations in the sample e g s x bar It is known Used to get info about the population What are the differences between population and sample distribution C Normal Distribution 1 Properties area under the curve equals to probability of occurrence symmetric across the mean each side contains the probability of 0 5 mean median mode total area under the curve 1 bell shaped 2 Empirical rule Area of 0 68 2 0 34 3 Standard normal distribution has a mean of 0 and a standard deviation of 1 Review of Basic Statistics Part II Distribution Chapter 14 Bold and Italic typed is my prediction that it will appear on the exam A Variables and statistics Variable characteristics of interest of population or sample Variable of interests of population is very large infinite while it is the opposite for sample Comparison between sample and population B Graphical summaries of descriptive statistics Open ended question word cloud Nominal and ordinal data pie chart bar chart and frequency table Interval and ratio histogram Test whether nominal and ordinal data use bar chart or histogram Why can t we use pie chart to represent interval or ratio data Hard to summarize and interpret C Graphical summaries of descriptive statistics Measure of central tendency and calculations median median mode Remember median requires arranging data from small to large When to use mean or median Median is suitable for skewed data as skewedness will affect the mean Numerical summaries measures of dispersion Variance standard deviation and range Cannot report means and standard deviation for nominal and ordinal data i ii D Application of statistics to marketing research first use descriptive statistics Review of Inferential Statistics Sampling distributions and CLM Bold and Italic typed is my prediction that it will appear on the exam A Sampling distribution of sample mean Understand the population variable of interest and truth of population 1 Sampling distribution of sample mean sampling distribution of sample mean is all possible values of x bar for across all possible samples of the same size 2 Central Limit Theorem for any variable regardless of its distribution the distribution of variable will approach a normal distribution as n increases implications mean of X bar mean of X standard error sigma divided by square root of n the result holds for any distribution 3 Distributions of interest i population distribution smooth line again it is unknown ii sample distribution frequency distribution of observations of variable in the sample x bar and s again it is known iii Sampling distribution THEORETICAL frequency distribution of ALL possible sample means mean of X bar and standard error B Applying the CLT 1 Analysis of ordinal nominal data want to know the population proportion because it is not ratio interval data use sample proportion to infer the population proportion ratio can transform ratio interval data to nominal ordinal data 2 Know the formula of calculating sample proportion