- 8-3.1: In what ways is the t distribution similar to the standard normal d...
- 8-3.2: What are the degrees of freedom for the t test?
- 8-3.3: Find the critical value (or values) for the t test for each. a. n _...
- 8-3.4: (ans) Using Table F, find the P-value interval for each test value....
- 8-3.5: Veterinary Expenses of Cat Owners According to the American Pet Pro...
- 8-3.6: Park Acreage A state executive claims that the average number of ac...
- 8-3.7: Cell Phone Call Lengths The average local cell phone call length wa...
- 8-3.8: Commute Time to Work A survey of 15 large U.S. cities finds that th...
- 8-3.9: Heights of Tall Buildings A researcher estimates that the average h...
- 8-3.10: Exercise and Reading Time Spent by Men Men spend an average of 29 m...
- 8-3.11: Television Viewing by Teens Teens are reported to watch the fewest ...
- 8-3.12: Internet Visits AU.S. Web Usage Snapshot indicated a monthly averag...
- 8-3.13: Cost of Making a Movie During a recent year the average cost of mak...
- 8-3.14: Chocolate Chip Cookie Calories The average 1-ounce chocolate chip c...
- 8-3.15: Cell Phone Bills The average monthly cell phone bill was reported t...
- 8-3.16: Water Consumption The Old Farmers Almanac stated that the average c...
- 8-3.17: Doctor Visits A report by the Gallup Poll stated that on average a ...
- 8-3.18: Number of Jobs The U.S. Bureau of Labor and Statistics reported tha...
- 8-3.19: Teaching Assistants Stipends A random sample of stipends of teachin...
- 8-3.20: Average Family Size The average family size was reported as 3.18. A...
Solutions for Chapter 8-3: t Test for a Mean
Full solutions for Elementary Statistics: A Step by Step Approach 8th ed. | 8th Edition
2 k p - factorial experiment
A fractional factorial experiment with k factors tested in a 2 ? p fraction with all factors tested at only two levels (settings) each
A study in which a sample from a population is used to make inference to a future population. Stability needs to be assumed. See Enumerative study
The portion of the variability in a set of observations that can be traced to speciic causes, such as operators, materials, or equipment. Also called a special cause.
A horizontal line on a control chart at the value that estimates the mean of the statistic plotted on the chart. See Control chart.
A probability distribution for a continuous random variable.
A term used for the quantity ( / )( ) 1 1 2 n xi i n ? = that is subtracted from xi i n 2 ? =1 to give the corrected sum of squares deined as (/ ) ( ) 1 1 2 n xx i x i n ? = i ? . The correction factor can also be written as nx 2 .
A square matrix that contains the correlations among a set of random variables, say, XX X 1 2 k , ,…, . The main diagonal elements of the matrix are unity and the off-diagonal elements rij are the correlations between Xi and Xj .
A measure of association between two random variables obtained as the expected value of the product of the two random variables around their means; that is, Cov(X Y, ) [( )( )] =? ? E X Y ? ? X Y .
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.
Defects-per-unit control chart
See U chart
The response variable in regression or a designed experiment.
Discrete random variable
A random variable with a inite (or countably ininite) range.
The amount of variability exhibited by data
A study in which a sample from a population is used to make inference to the population. See Analytic study
Erlang random variable
A continuous random variable that is the sum of a ixed number of independent, exponential random variables.
Estimate (or point estimate)
The numerical value of a point estimator.
Fixed factor (or fixed effect).
In analysis of variance, a factor or effect is considered ixed if all the levels of interest for that factor are included in the experiment. Conclusions are then valid about this set of levels only, although when the factor is quantitative, it is customary to it a model to the data for interpolating between these levels.
Fractional factorial experiment
A type of factorial experiment in which not all possible treatment combinations are run. This is usually done to reduce the size of an experiment with several factors.
A function used in the probability density function of a gamma random variable that can be considered to extend factorials
Effects in a fractional factorial experiment that are used to construct the experimental tests used in the experiment. The generators also deine the aliases.