Stats Test 2 Review
invalid.
"In American History, 20 students failed. Only 11 students failed World History. American History must be a more difficult course than World History." This statement is misleading because the measurement "number of students who fail" used as a surrogate for "difficulty of course" is
confidentiality of individual data.
A Census Bureau report on the income of Americans says with 90% confidence the median income of all California households in 2007 was $67,484 with a margin of error of ± $375. The Census Bureau never shares information about individuals with the IRS. To do so would violate a basic requirement of data ethics, namely
eliminate a possible source of bias.
A double-blind experiment was conducted to evaluate the effectiveness of the Salk polio vaccine. The purpose of keeping the diagnosing physicians ignorant of the treatment status of the experimental subjects was to
37% plus 41% is not 100%.
A student reports that of a simple random sample of 200 college undergraduates, 37% were female and 41% were male. We know that the student has made a mistake because
confounding.
A study of the effect of government job training programs finds that the pay of workers after training is higher than it was before training. A critic points out that workers often enroll for training when their pay has recently dipped. So the effect of training in raising pay is mixed up with the fact that pay would often rise when we measure from a low point. The statistical term for this effect is
about 12,000
According to the FBI Uniform Crime Report, the robbery rate in the United States is 202 per 100,000 people. At that rate, how many robberies would there be in a state the size of Indiana (5.8 million people)?
information about individual subjects is never made public.
All statistical studies should follow the principle of confidentiality. This means that
keep data on individuals confidential/get informed consent before collecting data.
All statistical studies that collect data from people should follow some basic ethical standards. Some of these ethical standards are
19%
Amy wants to spend a summer in France after she graduates. She is worried that this will be too expensive because the dollar buys fewer French francs now. When Amy entered college, a dollar was worth 6.5 francs. Now a dollar is worth only 5.25 francs. By about what percent has the value of the dollar in francs decreased?
It's nonsense, because removing 100% of the heartburn already removes all of it.
An ad for a new heartburn treatment says that it "reduces heartburn by 300%." What does this mean?
matched pairs
An experiment compares two brands of automobile tires. Each of a number of cars is equipped with one tire of each brand on a rear wheel (the order is randomized from car to car) and tread wear is measured periodically. This is called a
the nature of the study must be explained in advance to the subjects and they must voluntarily agree to take part.
Any statistical study that uses human subjects requires informed consent. This means that
the institutional review board must agree that subjects are adequately protected from possible harm.
Before any study that uses human subjects can be done at a university,
13.4%.
Before starting a weight reduction program, Joe weighed 216 pounds. At the end of the program, he weighed 187 pounds. This is a percentage loss of
not asking subjects to agree to participate without first informing them of the nature of the study and possible risks and benefits.
Ethical standards for randomized, controlled clinical trials include
not valid.
IQ tests are intended to measure "general problem-solving ability," which is what we mean by intelligence. Some experts think IQ tests measure not intelligence but how much education and how much exposure to middle-class culture you have. These experts say that IQ tests are
6.0%
In August of 2008, the price of Apple Computers common stock rose from $159.90 per share to $169.53 per share. What percent increase is this?
informed consent.
Not asking subjects to agree to participate in a study without first informing them of the nature of the study and possible risks and benefits is called
avoid confounding.
Randomization in experimental design is used to
advance review by an institutional review board/informed consent by the subjects.
Research studies that collect data from people must follow ethical guidelines. Some basic ethical principles for these studies are
be sure that the subjects of the study are safe.
Studies with human subjects must be approved in advance by an institutional review board. The board's main purpose is to
confidential.
Study in which information about individual subjects is never made public is said to be
not reliable.
The Environmental Protection Agency sends four identical samples of polluted water to the Acme Chemical Analysis Laboratory. The lab measures the amount of dioxin in each sample. The lab reports dioxin concentrations of 141, 323, 74, and 923 parts per billion. You can see that dioxin measurements made by Acme are
6.6%.
The average wage of production workers (adjusted for the effects of inflation) was $11.08 an hour in 1981 and $10.35 an hour in 1991. In the decade of the 1980s, wages went down by about
approval by a review board, informed consent, and confidentiality of data.
The basic ethical requirements for any study of human subjects are
be reliable but somewhat biased.
The diameter of a metal rod was measured eight times and the results in millimeters were 31.7, 31.7, 31.8, 31.7, 31.7, 31.8, 31.8 The true diameter of the rod is 31 millimeters. The measurement process appears to
an experiment imposes treatments on subjects, while an observational study accepts existing treatments.
The difference between an experiment and an observational study is
a well-designed experiment can give good evidence that the treatments actually cause the response.
The most important advantage of experiments over observational studies is
22%.
The net asset value of a mutual fund has increased from $27 on December 31 to $33 now. The percent increase in value is about
$772
The price of gold was $834 per ounce on December 31, and has dropped 7.43% since that time. What is the price per ounce now?
compare several treatments; use chance to assign subjects to treatments.
Two essential features of all statistically designed experiments are
Block A is chosen randomly from among the available subjects.
Which of the following statements about a randomized block design with two treatments is not true?
not valid.
You might try to measure how rich a person is by looking at the car they drive. In fact, driving a fancy car has little to do with income (most luxury cars are leased). In statistical terms, measuring income by car model is
The reason that block designs are sometimes used in experimentation is to
reduce sampling variability
