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The Department of Education wishes to estimate the proportion of all college students who have a job off-campus. It surveyed 1600 randomly selected students; 451 had such jobs. The population of interest to the Department of Education is:
all college students who have a job off campus.
none of these answers.
all college students
all 1600 students surveyed.
the 451 students in the survey who have off-campus jobs.
all college students
Is weight in lb nominal, ordinal, interval, or ratio?
Ratio
Ordinal
Interval
Nominal
ratio
nominal
labels/categories
interval
numbers with no true zero
ratio
numbers with true zero
ordinal
ordered categories (ranking)
Managers at a hospital are interested in the length of stay (in days) of open-heart patients who underwent surgery within the last year. Thirty five open-heart surgery patients admitted to the hospital within the last year are selected. Identify the population, sample, parameter, statistic, and variable in this problem.
thirty five open-heart patients who underwent surgery in the last year
sample
Managers at a hospital are interested in the length of stay (in days) of open-heart patients who underwent surgery within the last year. Thirty five open-heart surgery patients admitted to the hospital within the last year are selected. Identify the population, sample, parameter, statistic, and variable in this problem.
average length of stay of all open-heart patients who underwent surgery in the last year
parameter
Managers at a hospital are interested in the length of stay (in days) of open-heart patients who underwent surgery within the last year. Thirty five open-heart surgery patients admitted to the hospital within the last year are selected. Identify the population, sample, parameter, statistic, and variable in this problem.
length of hospital stay
variable
Managers at a hospital are interested in the length of stay (in days) of open-heart patients who underwent surgery within the last year. Thirty five open-heart surgery patients admitted to the hospital within the last year are selected. Identify the population, sample, parameter, statistic, and variable in this problem.
all open-heart patients who underwent surgery in the last year
population
Managers at a hospital are interested in the length of stay (in days) of open-heart patients who underwent surgery within the last year. Thirty five open-heart surgery patients admitted to the hospital within the last year are selected. Identify the population, sample, parameter, statistic, and variable in this problem.
average length of stay of the thirty five selected open-heart patients
statistic
A researcher wishes to estimate the average amount spent per person by visitors to a theme park. She takes a random sample of forty visitors and obtains an average of $28 per person. The population of interest is
$28 per person.
theme park researchers.
visitors to the theme park.
the amount of money spent per person.
the forty selected visitors.
visitors to the theme park.
quantitative discrete
can only take on a limited number of values (e.g., only whole numbers)
quantitative continuous
can take on any value and any value between two values (e.g., out to an infinite number of decimal places).
qualitative
data that is descriptive and depicts qualities or characteristics
cluster sampling
divide a population into clusters, such as districts or schools, and then randomly select some of these clusters as your sample
simple random
researcher randomly selects a subset of participants from a population
stratified sampling
researchers divide subjects into subgroups called strata based on characteristics that they share (10 random freshmen, sophomores,etc.)
systematic sampling
ordered sampling frame (every tenth person)
convenience sampling
easiest for the researcher to access (asking people in your class)
right skewed graph (mean ? median)
mean > median
Left skewed graph (mean ? median)
mean < median
bimodal graph
two peaks
uniform graph
no real peak, all level
Which of the following would NOT be an appropriate measure of central tendency when looking at incomes of a middle class neighborhood when one neighbor just sold their startup idea to Facebook for $1,000,000?
Mean
No other answer choice was an acceptable measure of central tendency
Median
All other answer choices are acceptable measures of central tendency
Mode
mean
what is the symbol for sample mean?
x̄
The square root of the ____(a)_____ is called the ____(b)_____ .
(a) variance
(b) standard deviation
(a) mean
(b) median
(a) standard deviation
(b) variance
(a) median
(b) mean
(a) variance
(b) standard deviation
median
the middle number in a sorted ascending or descending list of numbers
mode
number that occurs most
What is the symbol for sample standard deviation?
s (fancy s)
All of the following are measures of central tendency EXCEPT:
standard deviation
mode
mean
median
standard deviation
The 54th percentile in a large data set is 98.6. Approximately what percentage of the observations are greater than 98.6?
50%
98.6%
54%
46%
1.4%
46%
The score made by a particular student on a national standardized exam is the 65th percentile. This means that
His score is 65% of the average score.
About 65% of all scores on the exam were higher than his.
About 65% of all scores on the exam were lower than his.
His score is the 65th best on the exam.
He got about 65% of the answers correct.
About 65% of all scores on the exam were lower than his.
negative z-score
lower than mean
positive z-score
higher than mean
z-score equaiton =
(n - mean) / standard deviation (n is number in problem)
A researcher wants to determine the average income of the employed people of Omaha, Nebraska. He found that there are 385,600 employed people in the state. A group of 1,200 people are selected randomly to ascertain the income of each of those individuals. He finds that the average income of those 1,200 numbers to be $42,827. Identify the population in this context.
385,600 – 1,200 constitute the population
1,200 people selected for the study
385,600 employed people in Omaha
Average income of $42,827
385,600 + 1,200 constitute the population
385,600 employed people in Omaha
What is the symbol for population variance?
σ^2
When is the mode most useful?
Never
Categorical data
Numerical data
Numerical data when significant outliers are present
Categorical data
Mean, median, and mode are all measures of the ____ of a data set, while variance and standard deviation measure the ____ of a data set.
center, spread
Which of the following statistics is least impacted by outliers?
Mode
Mean
Range
Median
Variance
median
