 74.1: Do the data represent a population or a sample?
 74.2: Select a random sample of 12 ages and find the variance and standar...
 74.3: Find the 95% confidence interval of the standard deviation.
 74.4: Find the standard deviation of all the data values.
 74.5: Does the confidence interval calculated in question 3 contain the m...
 74.6: If it does not, give a reason why.
 74.7: What assumption(s) must be considered for constructing the confiden...
 74.8: Age of College Students Find the 90% confidence interval for the va...
 74.9: NewCar Lease Fees A newcar dealer is leasing various brandnew mo...
 74.10: Stock Prices A random sample of stock prices per share (in dollars)...
 74.11: Oil Changes A service station advertises that customers will have t...
 74.12: Home Ownership Rates The percentage rates of home ownership for 8 r...
 74.13: Calculator Battery Lifetimes A confidence interval for a standard d...
Solutions for Chapter 74: Confidence Intervals and Sample Size
Full solutions for Elementary Statistics: A Step by Step Approach  7th Edition
ISBN: 9780073534978
Solutions for Chapter 74: Confidence Intervals and Sample Size
Get Full SolutionsElementary Statistics: A Step by Step Approach was written by and is associated to the ISBN: 9780073534978. This textbook survival guide was created for the textbook: Elementary Statistics: A Step by Step Approach, edition: 7. Chapter 74: Confidence Intervals and Sample Size includes 13 full stepbystep solutions. Since 13 problems in chapter 74: Confidence Intervals and Sample Size have been answered, more than 32507 students have viewed full stepbystep solutions from this chapter. This expansive textbook survival guide covers the following chapters and their solutions.

Alias
In a fractional factorial experiment when certain factor effects cannot be estimated uniquely, they are said to be aliased.

Attribute control chart
Any control chart for a discrete random variable. See Variables control chart.

Bayes’ theorem
An equation for a conditional probability such as PA B (  ) in terms of the reverse conditional probability PB A (  ).

C chart
An attribute control chart that plots the total number of defects per unit in a subgroup. Similar to a defectsperunit or U chart.

Causeandeffect diagram
A chart used to organize the various potential causes of a problem. Also called a ishbone diagram.

Conditional probability
The probability of an event given that the random experiment produces an outcome in another event.

Conidence coeficient
The probability 1?a associated with a conidence interval expressing the probability that the stated interval will contain the true parameter value.

Covariance matrix
A square matrix that contains the variances and covariances among a set of random variables, say, X1 , X X 2 k , , … . The main diagonal elements of the matrix are the variances of the random variables and the offdiagonal elements are the covariances between Xi and Xj . Also called the variancecovariance matrix. When the random variables are standardized to have unit variances, the covariance matrix becomes the correlation matrix.

Defect
Used in statistical quality control, a defect is a particular type of nonconformance to speciications or requirements. Sometimes defects are classiied into types, such as appearance defects and functional defects.

Defectsperunit control chart
See U chart

Designed experiment
An experiment in which the tests are planned in advance and the plans usually incorporate statistical models. See Experiment

Discrete uniform random variable
A discrete random variable with a inite range and constant probability mass function.

Erlang random variable
A continuous random variable that is the sum of a ixed number of independent, exponential random variables.

Error mean square
The error sum of squares divided by its number of degrees of freedom.

Event
A subset of a sample space.

Extra sum of squares method
A method used in regression analysis to conduct a hypothesis test for the additional contribution of one or more variables to a model.

F distribution.
The distribution of the random variable deined as the ratio of two independent chisquare random variables, each divided by its number of degrees of freedom.

Fisher’s least signiicant difference (LSD) method
A series of pairwise hypothesis tests of treatment means in an experiment to determine which means differ.

Fraction defective
In statistical quality control, that portion of a number of units or the output of a process that is defective.

Gamma function
A function used in the probability density function of a gamma random variable that can be considered to extend factorials