STAT 2507 Study Guide - Midterm Guide: Statistical Parameter, Null Hypothesis, Type I And Type Ii Errors

180 views11 pages

goldgiraffe359

25 Mar 2017

School

Department

Course

Professor

For unlimited access to Study Guides, a Grade+ subscription is required.

Document Summary

Descriptive statistics: the procedures used to summarize and describe the important characteristics of a set of measurements contain: Graphical (pie chart, stem and leaf, histogram, boxplot, scatterplot) Numerical summary measures (mean, median, variance, standard deviation) Inferential statistics: procedures used to make inferences about population characteristics from information contained in a sample drown from this population contain: Population is the set of all measurements of interest to the investigator. Sample is a subset of measurements selected from the population of interest. Variable is a characteristic that changes or varies over time and/or for diferent individuals or objects under consideration. Experimental unit is the individual or object on which a variable is measured. Qualitative variables measure a quality or characteristic on each experimental unit. Quantitative variables measure a numerical quantity or amount on each experimental unit. Discrete variable is almost always result from counting and its possible values are.

Related Questions

Opeele Kyinkafa sells different used 2005 GM cars in excellent condition. The value or the retail price (Price) of a car is dependent on a variety of characteristics such as number of miles the car has been driven (Mileage), manufacturer of the car (Make) such as Buick, Cadillac, Chevrolet, Pontiac, SAAB, and Saturn. The car price is also influenced by the body type (Type) such as sedan, convertible, coupe, hatchback and wagon. It is also affected by number of cylinders (Cylinders) in the engine, the engine size (Liter), cruise control which is an indicator variable representing whether the car has cruise control (yes) or no otherwise and Sound indicator representing whether the car has upgraded speakers (yes) or no otherwise. All cars in this data set were less than one year old when priced and considered to be in excellent condition. Determine which major variables are dummies and are dynamic? Identify 3 potential unobserved heterogenous factors in this dataset. Display the full descriptive statistics of the data in R. Why do you think some variables are starred (*)? What is the median for “price”, standard deviation for “mileage”, skewness for “cylinder” and mean for “sound”? Test if “price” is normally distributed using histogram, kernel density plot and the shapiro wilk test. Create a red scatterplot matrix of price, mileage, cylinder, liter, make. From your graph, is the correlation between price & mileage positive or negative? What’s the pearson correlation coefficient between price & mileage and between “cylinder” & “liter” correct to 2 d.p Create a correlation matrix of the dataset by finding the apt R command for converting all string/dummy variables From the matrix, identify 2 potentially good predictors? Identify 3 pairs of variables that are mostly multicollinear. Which 2 pairs of variables are least correlated? Identify 3 pairs of variables most highly correlated with Cylinder Generate a simple regression plot of price on mileage with a re fitted line. Run the whole multiple regression model (label the equation as "regprice") & use it to answer the other questions. Specify the regression model for the whole data keeping the exact names of the variables. Write the estimated regression equation. In one sentence, which variables are significant and which are not? Justify Is the regression model justifiable? Explain Interpret the coefficient of Mileage, MakeCadillac, TypeSedan, Cylinder, & Cruiseyes. Compare the price of a car with 130,000 mileage, 6 cylinders, 3.8 liters, with cruise and sound, was manufactured by Pontiac with a convertible body type with that of the price of a car with four cylinders, 120,000 mileage, 3.8 liters, without cruise nor sound, was manufactured by Cadillac with a hatchback body type. Which factor(s) appears to be causing a comparative difference (if any)? Using only the VIF, which one of the pairs of variables selected to be multicollinear may be deleted? Justify?

aquamarineporpoise659

STAT 2507 Study Guide - Midterm Guide: Statistical Parameter, Null Hypothesis, Type I And Type Ii Errors

Document Summary

Get access

Related textbook solutions

Introductory Statistics

Related Documents

STAT 2507 Study Guide - Sample Maximum And Minimum, Set Theory, Exponential Decay

STAT 2507 Lecture Notes - Lecture 1: Statistical Unit, Univariate, Descriptive Statistics

STAT 2507 Chapter Notes - Chapter 2: Standard Deviation, Quartile, Interquartile Range

Related Questions