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statistics practice final

Terms in this set (23)

small margins of error with high levels of confidence will require _____________.
A. a large number of observations
B. a large population
C. discrete data
D. a small number of observations
A. a large number of observations
The median age of five people in a meeting is 30 years. One of the people, whose age is 50 years, leaves the room. What is the median age of the remaining four people in the room?
A. 40 years
B. 30 years
C. 25 years
D. cannot be determined from the information given
D. cannot be determined from the information given
The organization that reviews all planned studies is called the
A. Institutional Review Board
B. Informed Consent Panel
C. Confidentiality Committee
D. None of the above
A. Institutional Review Board
Many people are fearful of flying with certain airline carriers if the carrier has experienced a major crash in the past. This decision not to fly on certain airlines solely because of a single crash is an example of __________.
A. exploratory data analysis
B. anecdotal evidence
C. available data
D. statistical interference
B. anecdotal evidence
If in a game of checkers, each player's goal is to win the game, then each move is considered ___________
A. independent
B. dependent
B. dependent
which type of transformation may help change a curved relationship into a more linear relationship?
A. arcsin
B. cubed root
C. reciprocal
D. log
D. log
In a test of statistical hypotheses, what does the P-value tell us?
A. The smallest level of significance at which the null hypothesis can be rejected
B. the largest level of significance at which the null hypothesis can be rejected
C. if the null hypothesis is true
D. if the alternative hypothesis is true
A. The smallest level of significance at which the null hypothesis can be rejected
The chi-square goodness of fit test is for use on data with _____ variables.
A. quantitative
B. categorical
C. quantitative or categorical
B. categorical
A variable is a characteristic of a
A. case
B. label
C. value
D. none of the above
A. case
suppose you have two math classes (math 1 and math 2) and two science courses (science 1 and science 2) that you must complete before your sophomore year in college. Suppose you are required to take at least one of the science courses during your freshman year. What is the event A of required science courses you could take the first semester of your freshman year?
A. A = {1, 2}
B. A = {science 1, science 2, science 1 and 2}
C. A = {1}
D. A = {math 1, math 2, science 1, science 2}
B. A = {science 1, science 2, science 1 and 2}
To investigate whether or not sending text messages while driving impacts driving ability, we had 100 participants (50 men and 50 women) drive an obstacle course under one of the following conditions: 1) no texting while driving, 2) sending 5 messages while driving, 3) sending 10 messages while driving. We measured the accuracy with which the subjects drove the obstacle course from a scale of 1 to 10 (1=poor and 10=excellent). what type of study is this?
A. an experiment
B. a matched pairs study
C. an observational study
A. an experiment
True or false. the binomial distribution is a continuous distribution.
False
A college newspaper interviews a psychologist about a proposed system for rating the teaching ability of faculty members. The psychologist says, "The evidence indicates that the correlation between a faculty member's research productivity and teaching rating is close to zero." What would be a correct interpretation of this statement?
A. Good researchers tend to be poor teachers and vice versa
B. Good researchers are just as likely to be good teachers as they are bad teachers. Likewise for poor researchers
C. Good teachers tend to be poor researchers and vice versa
D. Good research and good teaching go together.
B. Good researchers are just as likely to be good teachers as they are bad teachers. Likewise for poor researchers
Two variables are positively associated when ______
A. above average values of one tend to accompany above average values of the other and vice versa
B. above-average values of one tend to accompany below-average values of the other and vice versa
C. both variables have an outlier
D. none of the above
A. above-average values of one tend to accompany above-average values of the other and vice versa
Which of the following statements best describes the difference between an observational study and an experiment?
A. In an experiment the researcher is careful to determine exactly what is to be observed, whereas in an observational study there is greater concern about how the observations are made.
B. In an experiment the data are obtained using careful controls on the treatments, but in an observational study the data are obtained through careful observation of the responses.
C. There are really no significant differences between observational studies and experiments. They are different names for essentially the same type of study.
D. In an experiment treatments are deliberately imposed upon individuals and their responses are observed. However, in an observational study without any attempt to influence the responses, individuals and variables of interest are measured.
E. Without concrete examples, it is not possible to detect what the differences might be.
D. In an experiment treatments are deliberately imposed upon individuals and their responses are observed. However, in an observational study without any attempt to influence the responses, individuals and variables of interest are measured.
Olivia is planning to take a foreign language class. To research how satisfied other students are with their foreign language classes, she decides to take a sample of 20 such students. The university offers classes in four languages. She will select a sample of five students from each language. Olivia asks the instructors of the 20 selected students to have the students rate the class they are currently enrolled in. If Olivia plans to use these ratings to learn about how satisfied all foreign language students are, why will the results be questionable?
A. Because she used voluntary response
B. Because of nonresponse bias
C. because of response bias
D. because she used a poorly worded question
C. because of response bias
An agricultural researcher plants 25 plots with a new variety of yellow corn. Assume that the yield per acre for the new variety of yellow corn follows a Normal distribution with an unknown mean of mu and a standard deviation of 10 bushels per acre. Which of the following would produce a confidence interval with a smaller margin of error than the 90% confidence interval?
A. Plant 10 plots rather than 25 because a smaller sample size will result in a smaller margin of error
B. Plant only 5 plots because 5 are easier to manage and control
C. Compute a 99% interval rather than a 90% confidence interval because a higher confidence level will result in a smaller margin of error.
D. plant 100 plots rather than 25 because a larger sample size will result in a smaller margin of error.
D. plant 100 plots rather than 25 because a larger sample size will result in a smaller margin of error.
100 volunteers who suffer from severe depression are available for a study. 50 are selected at random and are given a new drug that is thought to be particularly effective in treating severe depression. A psychiatrist evaluates the symptoms of all volunteers after 4 weeks in order to determine if there has been substantial improvement in the severity of the depression. What is the explanatory variable or factor in this study?
A. the use of a psychiatrist to evaluate the severity of depression.
B. the extent to which the depression was reduced
C. which drug the volunteers receive
D. The use of randomization and the fact that this was a comparative study
C. Which drug the volunteers receive
What is the best way to control for lurking variables?
A. Compare two or more treatments
B. Randomize to assign experimental units to treatments
C. Repeat each treatment on many units
D. None of the above.
B. Randomize to assign experimental units to treatments
The first day of class, the Professor collects information on each student to make a data set that will be analyzed throughout the semester. The information asked includes hometown, GPA, number of classes taking, number of siblings, and favorite subject. How many quantitative variables are in this data set?
A. 1
B. 2
C. 3
D. 4
C. 3
An engineer has designed an improved light bulb. The previous design had an average lifetime of 1200 hours. Using a sample of 2000 of these new bulbs the average lifetime of this improved lightbulb is found to be 1201 hours. Although the difference is quite small, the effect was statistically significant at the 0.05 level. Suppose that, in fact, there is no difference between the mean lifetimes of the previous design and the new design. Which of the following statements is TRUE?
A. type 1 error has been committed
B. type 2 error has been committed
C. No error has been committed.
A. Type 1 error has been committed
The F distributions are a family of distributions with how many parameters?
A. 3
B. 0
C. 2
D. 1
C. 2
In order assess the effects of exercise on reducing cholesterol, a researcher sampled 50 people from a local gym who exercised regularly and 50 people from the surrounding community who it was assumed did not exercise regularly. Each subject reported to a clinic to have their cholesterol measured. The subjects were unaware of the purpose of the study, and the technician measuring the cholesterol was not aware of whether the subjects exercised regularly or not. What type of study is this?
A. double blind experiment
B. an experiment but not double blind
C. an observational study
D. a matched pairs experiment
C. an observational study
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