analyze statistics from two samples‚ and the hypothesis and confidence interval would deal with the difference between two population means. The following factors are important in hypothesis testing: 1. probability theory 2. the sampling distribution of the statistic 3. the errors inherent in hypothesis testing and estimation 4. the level of significance and the level of confidence 5. the directional nature of the alternative hypothesis General Procedure 1. State the hypotheses
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Getting Started with MegaStat J. B. Orris Butler University Copyright 2002 by J. B. Orris ® Table of Contents 1. Basic Procedures............................................................................................................ 2 Buttons ........................................................................................................................... 3 Data Selection ................................................................................................
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A hypothesis is a claim Population mean The mean monthly cell phone bill in this city is μ = $42 Population proportion Example: The proportion of adults in this city with cell phones is π = 0.68 States the claim or assertion to be tested Is always about a population parameter‚ not about a sample statistic Is the opposite of the null hypothesis e.g.‚ The average diameter of a manufactured bolt is not equal to 30mm ( H1: μ ≠ 30 ) Challenges the status quo Alternative never contains
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to generalize from our sample to the population. Now‚ we know that the sampling distribution model is centered at the true proportion‚ p‚ of all home owners who use electricity to heat their homes. But we don’t know p. it isn’t 34.0%. That’s the p̂ from our sample. What we do know is that the sampling distribution model of p̂ centered at p‚ and we know that the standard deviation of the sampling distribution is SE(p̂) = √ p̂ q̂/n = √(.34)(1-.34)/3500 = 0.008 Because our sample (3500)
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Validity- does the variable accurately reflect the phenomenon you are trying to measure. Reliability- does the indicator consistently assign the same number. Cross-sectional data- no time/multiple entries. Panel data set- multiple entries/over time. Time series-one entry/time. Population: the total set of items or people that a researcher is interested in studying. Sample: a subset of the population- random or nonrandom. Goal is to be representative of population.Criteria for evaluating causal relationships
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expected value is always greater than or equal to the variance. a. (ii) only b. (ii) and (iv) c. (iii) and (iv) d. (i)‚ (ii) and (iv). ____ 4. A normal distribution with a mean of 0 and a standard deviation of 1 is called a. a probability density function b. an ordinary normal curve c. a standard normal distribution d. none of these alternatives is
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© Government of Tamilnadu First Edition-2005 Revised Edition 2007 Author-cum-Chairperson Dr. K. SRINIVASAN Reader in Mathematics Presidency College (Autonomous) Chennai - 600 005. Authors Dr. E. CHANDRASEKARAN Dr. C. SELVARAJ Selection Grade Lecturer in Mathematics Presidency College (Autonomous) Chennai - 600 005 Lecturer in Mathematics L.N. Govt. College‚ Ponneri-601 204 Dr. THOMAS ROSY Senior Lecturer in Mathematics Madras Christian College‚ Chennai - 600 059 Dr
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Tutorial 07: Solutions Part A: For all your answers‚ please remember to do the following: 1. Draw curves 2. State the distribution 3. Define the variable A7.1 An automatic machine in a manufacturing process is operating properly if the lengths of an important subcomponent are normally distributed‚ with mean µ = 117 cm and standard deviation σ = 2.1 cm. If the machine is operating correctly: Let X = variable length of subcomponent (cm). Then if the machine is operating correctly‚ X ~ N (117‚ 2.12
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Introduction The old adage ‘what gets measured improves’ is reflected in the dramatic increase in the range and scope of data being collected today. We are barraged with statistics on sports results‚ economic indicators and politics: people are becoming familiar with scoring averages‚ inflation rates and voter satisfaction surveys. The advent of low-cost personal computers combined with the widespread availability of powerful computing software‚ such as Excel‚ means that many people have both
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1. As the degrees of freedom increase‚ the t distribution approaches the b. normal distribution 2. If the margin of error in an interval estimate of μ is 4.6‚ the interval estimate equals b. [pic] 3. The t distribution is a family of similar probability distributions‚ with each individual distribution depending on a parameter known as the c. degrees of freedom 4. The probability that the interval estimation procedure will generate an interval that does
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