- 7-4.1: Do the data represent a population or a sample?
- 7-4.2: Select a random sample of 12 ages and find the variance and standar...
- 7-4.3: Find the 95% confidence interval of the standard deviation.
- 7-4.4: Find the standard deviation of all the data values.
- 7-4.5: Does the confidence interval calculated in question 3 contain the m...
- 7-4.6: If it does not, give a reason why.
- 7-4.7: What assumption(s) must be considered for constructing the confiden...
- 7-4.8: Age of College Students Find the 90% confidence interval for the va...
- 7-4.9: New-Car Lease Fees A new-car dealer is leasing various brand-new mo...
- 7-4.10: Stock Prices A random sample of stock prices per share (in dollars)...
- 7-4.11: Oil Changes A service station advertises that customers will have t...
- 7-4.12: Home Ownership Rates The percentage rates of home ownership for 8 r...
- 7-4.13: Calculator Battery Lifetimes A confidence interval for a standard d...
Solutions for Chapter 7-4: Confidence Intervals and Sample Size
Full solutions for Elementary Statistics: A Step by Step Approach | 7th Edition
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.
An equation for a conditional probability such as PA B ( | ) in terms of the reverse conditional probability PB A ( | ).
An attribute control chart that plots the total number of defects per unit in a subgroup. Similar to a defects-per-unit or U chart.
A chart used to organize the various potential causes of a problem. Also called a ishbone diagram.
The probability of an event given that the random experiment produces an outcome in another event.
The probability 1?a associated with a conidence interval expressing the probability that the stated interval will contain the true parameter value.
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 off-diagonal elements are the covariances between Xi and Xj . Also called the variance-covariance matrix. When the random variables are standardized to have unit variances, the covariance matrix becomes the correlation matrix.
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.
Defects-per-unit control chart
See U chart
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.
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.
The distribution of the random variable deined as the ratio of two independent chi-square random variables, each divided by its number of degrees of freedom.
Fisher’s least signiicant difference (LSD) method
A series of pair-wise hypothesis tests of treatment means in an experiment to determine which means differ.
In statistical quality control, that portion of a number of units or the output of a process that is defective.
A function used in the probability density function of a gamma random variable that can be considered to extend factorials