 Chapter 21.21.1: Who uses instant messaging? Teenagers (ages 12 to 17) are much more...
 Chapter 21.21.2: How to quit smoking. Nicotine patches are often used to help smoker...
 Chapter 21.21.3: Broken crackers. We dont like to find broken crackers when we open ...
 Chapter 21.21.4: Inline skaters. A study of injuries to inline skaters used data f...
 Chapter 21.21.5: The Gold Coast.Coast in Africa suspects that the death rate was hig...
 Chapter 21.21.6: How to quit smoking, continued. Exercise 21.2 describes a randomize...
 Chapter 21.21.7: Take pM and p F to be the proportions of all college males and fema...
 Chapter 21.21.8: The sample proportions of college males and females who worked last...
 Chapter 21.21.9: The pooled sample proportion who worked last summer is about(a) p =...
 Chapter 21.21.10: The z statistic for a test comparing the proportions of college men...
 Chapter 21.21.11: The 95% largesample confidence interval for the difference pM p F ...
 Chapter 21.21.12: In an experiment to learn if substance M can help restore memory, t...
 Chapter 21.21.13: The z test in the previous exercise(a) may be inaccurate because th...
 Chapter 21.21.14: The plus four 90% confidence interval for the difference between th...
 Chapter 21.21.15: Genetically altered mice. Genetic influences on cancer can be studi...
 Chapter 21.21.16: Drug testing in schools. In 2002 the Supreme Court ruled that schoo...
 Chapter 21.21.17: I Do our emotions influence economic decisions? One way to examine ...
 Chapter 21.21.18: Exercise 21.16 describes a study thatcompared the proportions of at...
 Chapter 21.21.19: Does statistical help make a difference? Is there a significant dif...
 Chapter 21.21.20: How often are statisticians involved? Give a 95% confidence interva...
 Chapter 21.21.21: How big a difference? Give a 95% confidence interval for the differ...
 Chapter 21.21.22: A study by the National Athletic Trainers Associationsurveyed 1679 ...
 Chapter 21.21.23: Exercise 20.35 (page 509) describesa study in which batches of soyb...
 Chapter 21.21.24: Never forget that even small effects canbe statistically significan...
 Chapter 21.21.25: A sample survey asked 202 black parents and201 white parents of hig...
 Chapter 21.21.26: The sample survey described in the previous exercise alsoasked resp...
 Chapter 21.21.27: The proportion of drivers who use seat belts depends on thingslike ...
 Chapter 21.21.28: Here are data from the study described in theprevious exercise for ...
 Chapter 21.21.29: Lyme disease is spread in the northeastern United States byinfected...
 Chapter 21.21.30: Are urban students more successful? North Carolina State University...
 Chapter 21.21.31: Does preschool help? To study the longterm effects of preschool pr...
 Chapter 21.21.32: The North Carolina State University study(Exercise 21.30) also look...
 Chapter 21.21.33: The study in Exercise 21.31 randomly assigned 123 children tothe tw...
 Chapter 21.21.34: Are shoppers more or less likely to use credit cards forimpulse pur...
Solutions for Chapter Chapter 21: Comparing Two Proportions
Full solutions for The Basic Practice of Statistics  4th Edition
ISBN: 9780716774785
Solutions for Chapter Chapter 21: Comparing Two Proportions
Get Full SolutionsChapter Chapter 21: Comparing Two Proportions includes 34 full stepbystep solutions. This textbook survival guide was created for the textbook: The Basic Practice of Statistics, edition: 4. Since 34 problems in chapter Chapter 21: Comparing Two Proportions have been answered, more than 11151 students have viewed full stepbystep solutions from this chapter. This expansive textbook survival guide covers the following chapters and their solutions. The Basic Practice of Statistics was written by and is associated to the ISBN: 9780716774785.

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

Analysis of variance (ANOVA)
A method of decomposing the total variability in a set of observations, as measured by the sum of the squares of these observations from their average, into component sums of squares that are associated with speciic deined sources of variation

Arithmetic mean
The arithmetic mean of a set of numbers x1 , x2 ,…, xn is their sum divided by the number of observations, or ( / )1 1 n xi t n ? = . The arithmetic mean is usually denoted by x , and is often called the average

Bernoulli trials
Sequences of independent trials with only two outcomes, generally called “success” and “failure,” in which the probability of success remains constant.

Bias
An effect that systematically distorts a statistical result or estimate, preventing it from representing the true quantity of interest.

Bivariate distribution
The joint probability distribution of two random variables.

Confounding
When a factorial experiment is run in blocks and the blocks are too small to contain a complete replicate of the experiment, one can run a fraction of the replicate in each block, but this results in losing information on some effects. These effects are linked with or confounded with the blocks. In general, when two factors are varied such that their individual effects cannot be determined separately, their effects are said to be confounded.

Conidence level
Another term for the conidence coeficient.

Continuous random variable.
A random variable with an interval (either inite or ininite) of real numbers for its range.

Crossed factors
Another name for factors that are arranged in a factorial experiment.

Cumulative distribution function
For a random variable X, the function of X deined as PX x ( ) ? that is used to specify the probability distribution.

Curvilinear regression
An expression sometimes used for nonlinear regression models or polynomial regression models.

Decision interval
A parameter in a tabular CUSUM algorithm that is determined from a tradeoff between false alarms and the detection of assignable causes.

Degrees of freedom.
The number of independent comparisons that can be made among the elements of a sample. The term is analogous to the number of degrees of freedom for an object in a dynamic system, which is the number of independent coordinates required to determine the motion of the object.

Deining relation
A subset of effects in a fractional factorial design that deine the aliases in the design.

Deming
W. Edwards Deming (1900–1993) was a leader in the use of statistical quality control.

Enumerative study
A study in which a sample from a population is used to make inference to the population. See Analytic study

Experiment
A series of tests in which changes are made to the system under study

Exponential random variable
A series of tests in which changes are made to the system under study

Fraction defective control chart
See P chart