Statistics J-End2 GRADE A Q&A
c - (correct answer)SAT scores are normally distributed with mean 500 and standard
deviation 100. Julie scores 650. Her standard score is
a) 150
b) 15
c) 1.5
d) 0.15
b - (correct answer)SAT scores are normally distributed with mean 500 and standard
deviation 10. Julie scores 650. Her standard score is
a) 150
b) 15
c) 1.5
d) 0.15
b - (correct answer)If you know the mean and standard deviation of a distribution, do
you know the complete shape of the distribution?
a) Yes, always.
b) Yes if the distribution is normal, but not in general.
c) Yes if the distribution is symmetric, but not in general.
d) No, never.
b - (correct answer)You are told that your score on an exam is at the 85 percentile of the
distribution of scores. This means that
,a) You score was equal to or lower than approximately 85% of the people who took this
exam
b) You score was equal to or higher than approximately 85% of the people who took
this exam
c) You answered 85% of the questions correctly
d) The correlation between your score and the exam is 0.85.
e) You are 85% confident in your score is significant
a - (correct answer)The distribution of heights of adult men is approximately normal with
mean 69 inches and standard deviation 2.5 inches. How tall is a man whose
standardized height is -0.3?
a) 68.25 inches
b) 68.7 inches
c) 69.3 inches
d) 69.75 inches
e) Can't tell without the normal table from the text.
c - (correct answer)Wayne's buddy Garth took the SAT. His standard score on the SAT
was 0.3. This means that Garth's actual score was
a) more than 1 standard deviation below the mean SAT score.
b) less than 1 standard deviation below the mean SAT score.
c) less than 1 standard deviation above the mean SAT score.
d) more than 1 standard deviation above the mean SAT score.
e) Can't tell without knowing the standard deviation.
, b - (correct answer)The least-squares regression line for predicting blood alcohol
content from number of beers is y = -0.013 + 0.018x. The slope 0.018 of this line tells us
that
a) the correlation between number of beers and BAC is 0.018
b) on the average, BAC increases by 0.018 for each additional beer a student drinks
c) a student who drinks no beer will still have a BAC of 0.018
d) the average BAC of all the students in the study was 0.018
b - (correct answer)A "regression line" is not just any line drawn through the points of a
scatter plot. What is special about a regression line?
a) It passes through all the points.
b) It always uses the least-squares idea.
c) It has slope equal to the correlation between the two variables.
d) It describes how a response variable y changes as an explanatory variable x takes
different values.
a - (correct answer)You are planning an experiment to study the effect of gasoline brand
and vehicle weight on the gas mileage (miles per gallon) of sport utility vehicles. In this
study,
a) gas mileage is a response variable.
b) gas mileage is an explanatory variable.
c) gas mileage is a lurking variable.
d) gas mileage is a categorical variable.
b - (correct answer)Dice have six faces, showing 1 to 6 pips (spots). If a die is balanced,
all six faces are equally likely. What must be the probability of each face?
c - (correct answer)SAT scores are normally distributed with mean 500 and standard
deviation 100. Julie scores 650. Her standard score is
a) 150
b) 15
c) 1.5
d) 0.15
b - (correct answer)SAT scores are normally distributed with mean 500 and standard
deviation 10. Julie scores 650. Her standard score is
a) 150
b) 15
c) 1.5
d) 0.15
b - (correct answer)If you know the mean and standard deviation of a distribution, do
you know the complete shape of the distribution?
a) Yes, always.
b) Yes if the distribution is normal, but not in general.
c) Yes if the distribution is symmetric, but not in general.
d) No, never.
b - (correct answer)You are told that your score on an exam is at the 85 percentile of the
distribution of scores. This means that
,a) You score was equal to or lower than approximately 85% of the people who took this
exam
b) You score was equal to or higher than approximately 85% of the people who took
this exam
c) You answered 85% of the questions correctly
d) The correlation between your score and the exam is 0.85.
e) You are 85% confident in your score is significant
a - (correct answer)The distribution of heights of adult men is approximately normal with
mean 69 inches and standard deviation 2.5 inches. How tall is a man whose
standardized height is -0.3?
a) 68.25 inches
b) 68.7 inches
c) 69.3 inches
d) 69.75 inches
e) Can't tell without the normal table from the text.
c - (correct answer)Wayne's buddy Garth took the SAT. His standard score on the SAT
was 0.3. This means that Garth's actual score was
a) more than 1 standard deviation below the mean SAT score.
b) less than 1 standard deviation below the mean SAT score.
c) less than 1 standard deviation above the mean SAT score.
d) more than 1 standard deviation above the mean SAT score.
e) Can't tell without knowing the standard deviation.
, b - (correct answer)The least-squares regression line for predicting blood alcohol
content from number of beers is y = -0.013 + 0.018x. The slope 0.018 of this line tells us
that
a) the correlation between number of beers and BAC is 0.018
b) on the average, BAC increases by 0.018 for each additional beer a student drinks
c) a student who drinks no beer will still have a BAC of 0.018
d) the average BAC of all the students in the study was 0.018
b - (correct answer)A "regression line" is not just any line drawn through the points of a
scatter plot. What is special about a regression line?
a) It passes through all the points.
b) It always uses the least-squares idea.
c) It has slope equal to the correlation between the two variables.
d) It describes how a response variable y changes as an explanatory variable x takes
different values.
a - (correct answer)You are planning an experiment to study the effect of gasoline brand
and vehicle weight on the gas mileage (miles per gallon) of sport utility vehicles. In this
study,
a) gas mileage is a response variable.
b) gas mileage is an explanatory variable.
c) gas mileage is a lurking variable.
d) gas mileage is a categorical variable.
b - (correct answer)Dice have six faces, showing 1 to 6 pips (spots). If a die is balanced,
all six faces are equally likely. What must be the probability of each face?
