All but one of these statements contain a mistake. Which could be true?
A) The correlation between the amount of fertilizer used and the yield of beans is 0.42.
B) The correlation between a football player's weight and the position he plays is 0.54.
C) Th
A
A company sponsoring a new Internet search engine wants to collect data on the ease of using it.
Which is the best way to collect the data?
A) experiment
B) sample survey
C) census
D) simulation
E) observational study
b
Researchers studying growth patterns of children collect data on the heights of fathers and the heights of their 16 year old sons is most likely to be
A) near +0.7
B) near -1.0
C) exactly +1.0
D) somewhat greater than 1.0
E) near 0
a
A fair coin has come up "heads" 10 times in a row. The probability that the coin will come up heads on the next coin flip is
A) 50%
B) it cannot be determined
C) greater than 50%, since it appears that we are in a streak of "heads"
D) less than 50% since
a
According to the National Telecommunication and Information Administration, 56.5% of U.S.
households owned a computer in 2001. What is the probability that of three randomly selected U.S. households at least one owned a computer in 2001?
A) 56.5%
B) 18.0%
e
According to the National Telecommunication and Information Administration, 50.5% of U.S.
households had Internet access in 2001. What is the probability that four randomly selected U.S. households all had Internet access in 2001?
A) 50.5%
B) 93.5%
C) 12.
e
The January 2005 Gallup Youth Survey telephoned a random sample of 1028 U.S. teens and asked these teens to name their favorite movie from 2004. Napoleon Dynamite had the highest percentage with 8% of teens ranking it as their favorite movie. Which is tru
e
Suppose your local school district decides to randomly test high school students for attention deficit
disorder (ADD). There are three high schools in the district, each with grades 9-12. The school board pools all of the students together and randomly sa
c
A basketball player has a 70% free throw percentage. Which plan could be used to simulate the
number of free throws she will make in her next five free throw attempts?
I. Let 0,1 represent making the first shot, 2, 3 represent making the second shot,...,
e
More dogs are being diagnosed with thyroid problems than have been diagnosed in the past. A
researcher identified 50 puppies without thyroid problems and kept records of their diets for several years to see if any developed thyroid problems. This is a(n)
b
A chemistry professor who teaches a large lecture class surveys his students who attend his class
about how he can make the class more interesting, hoping he can get more students to attend. This survey method suffers from
A) nonresponse bias
B) none of t
c
Placebos are a tool for
A) randomization
B) sampling
C) blocking
D) control
E) blinding
e
Double-blinding in experiments is important so that
I. The evaluators do not know which treatment group the participants are in.
II. The participants do not know which treatment group they are in.
III. No one knows which treatment any of the participants
a
Which of the following is not required in an experimental design?
A) control
B) All are required in an experimental design.
C) randomization
D) replication
E) blocking
e
A researcher wants to compare the effect of a new type of shampoo on hair condition. The
researcher believes that men and women may react to the shampoo differently. Additionally, the researcher believes that the shampoo will react differently on hair tha
d
The auto insurance industry crashed some test vehicles into a cement barrier at speeds of 5 to 25
mph to investigate the amount of damage to the cars. They found a correlation of r = 0.60 between speed (MPH) and damage ($). If the speed at which a car hit
b
20) The correlation between X and Y is r = 0.35. If we double each X value, decrease each Y by 0.20, and
interchange the variables (put X on the Y-axis and vice versa), the new correlation
A) cannot be determined.
B) is 0.50
C) is 0.35
D) is 0.90
E) is 0.
c
A consumer group collected information on HDTVs. They created a linear model to estimate the
cost of an HDTV (in $) based on the screen size (in inches). Which is the most likely value of the slope of the line of best fit?
A) 7
B) 7000
C) 70
D) 700
E) 0.7
c
The correlation between a family's weekly income and the amount they spend on restaurant meals
is found to be r = 0.30. Which must be true?
I. Families tend to spend about 30% of their incomes in restaurants.
II. In general, the higher the income, the mor
b
A medical researcher finds that the more overweight a person is, the higher his pulse rate tends to
be. In fact, the model suggests that 12-pound differences in weight are associated with differences in pulse rate of 4 beats per minute. Which is true?
I.
d
Education research consistently shows that students from wealthier families tend to have higher
SAT scores. The slope of the line that predicts SAT score from family income is 6.25 points per $1000, and the correlation between the variables is 0.48. Then
a
A regression analysis of company profits and the amount of money the company spent on
advertising found r2 = 0.72. Which of these is true?
I. The model can correctly predict the profit for 72% of companies.
II. On average, about 72% of a company's profit
a
It's easy to measure the circumference of a tree's trunk, but not so easy to measure its height. Foresters developed a model for ponderosa pines that they use to predict the tree's height (in feet) from the circumference of its trunk (in inches): ln h ^ =
e
Two variables that are actually not related to each other may nonetheless have a very high
correlation because they both result from some other, possibly hidden, factor. This is an example of
A) an outlier.
B) leverage.
C) regression.
D) a lurking variabl
d
Residuals are...
A) none of these
B) variation in the data that is explained by the model.
C) the difference between observed responses and values predicted by the model.
D) data collected from individuals that is not consistent with the rest of the group
c
Which statement about influential points is true?
I. Removal of an influential point changes the regression line.
II. Data points that are outliers in the horizontal direction are more likely to be influential than points that are outliers in the vertical
e
Which is true?
I. Random scatter in the residuals indicates a model with high predictive power.
II. If two variables are very strongly associated, then the correlation between them will be near +1.0 or -1.0.
III. The higher the correlation between two var
c
School administrators collect data on students attending the school. Which of the following variables is quantitative?
A) whether the student has taken the SAT
B) grade point average
C) whether the student is in AP* classes
D) none of these
E) class (fres
b
Which of the following variables would most likely follow a Normal model?
A) weights of adult male elephants
B) scores on an easy test
C) heights of singers in a co-ed choir
D) all of these
E) family income
a
A professor has kept records on grades that students have earned in his class. If he wants to
examine the percentage of students earning the grades A, B, C, D, and F during the most recent term, which kind of plot could he make?
A) pie chart
B) dotplot
C)
a
Two sections of a class took the same quiz. Section A had 15 students who had a mean score of 80, and Section B had 20 students who had a mean score of 90. Overall, what was the approximate mean score for all of the students on the quiz?
A) 85.0
B) 84.3
C
c
Your Stats teacher tells you your test score was the 3rd quartile for the class. Which is true?
I. You got 75% on the test.
II. You can't really tell what this means without knowing the standard deviation.
III. You can't really tell what this means unless
b
Suppose that a Normal model described student scores in a history class. Parker has a standardized
score (z-score) of +2.5. This means that Parker
A) is 2.5 points above average for the class.
B) has a standard deviation of 2.5.
C) is 2.5 standard deviati
c
The advantage of making a stem-and-leaf display instead of a dotplot is that a stem-and-leaf
display
A) it satisfies the area principle
B) a stem and leaf display is for quantitative data while a dot plot shows categorical data
C) shows the shape of the d
e
Which of the following data summaries are changed by adding a constant to each data value?
I. the mean
II. the median
III. the standard deviation
From this information we know that
A) I, II, and III
B) I only
C) I and II
D) I and III
E) III only
c