BMAL-590 Quantitative Research
Another form of descriptive statistics uses numerical techniques to summarize data.
Rather than providing the raw data, the professor may only share summary data with
the student.
Histogram - CORRECT ANSWER-(or bar graph) can show if the data is evenly
distributed across the range of values, if it falls symmetrically from a center peak
(normal distribution), if there is a peak but the more of the data falls on one side of the
peak than the other (a skewed distribution), or if there are two or more peaks in the data
(bi- or multi-modal).
average - CORRECT ANSWER-mean
range - CORRECT ANSWER-calculated by subtracting the smallest number from the
largest.
mode - CORRECT ANSWER-the most frequently occurring score(s) in a distribution
variance - CORRECT ANSWER-the average squared deviation from the mean
What Is Statistics? - CORRECT ANSWER-"Statistics is a way to get information from
data."
Statistics is a tool for creating new understanding from a set of numbers.
You need data and information
descriptive statistics - CORRECT ANSWER-one of two branches of statistics which
focuses on methods of organizing, summarizing, and presenting data in a convenient
and informative way.
One form of descriptive statistics uses graphical techniques which allow statistics
practitioners to present data in ways that make it easy for the reader to extract useful
information.
Standard deviation - CORRECT ANSWER-the square root of the variance and gets the
variability measure back to the same units as the data. Standard deviation has many
useful properties when the data is normally distributed
inferential statistics - CORRECT ANSWER-a body of methods used to draw
conclusions or inferences about characteristics of populations based on sample data.
,Exit polls are a very common application of statistical inference.
Statistical inference problems involve three key concepts: - CORRECT ANSWER-
population, the sample, and the statistical inference.
Population: - CORRECT ANSWER-the group of all items of interest to a statistics
practitioner. It is frequently very large and may, in fact, be infinitely large. In the
language of statistics, population does not necessarily refer to a group of people. It may,
for example, refer to the population of diameters of ball bearings produced at a large
plant.
A descriptive measure of a population is called a parameter. In most applications of
inferential statistics, the parameter represents the information we need.
Sample - CORRECT ANSWER-a set of data drawn from the population. A descriptive
measure of a sample is called a statistic. We use statistics to make inferences about
parameters.
statistical inference - CORRECT ANSWER-the process of making an estimate,
prediction, or decision about a population based on sample data. Because populations
are almost always very large, investigating each member of the population would be
impractical and expensive. It is far easier and cheaper to take a sample from the
population of interest and draw conclusions or make estimates about the population on
the basis of information provided by the sample. However, such conclusions and
estimates are not always going to be correct. For this reason, we build into the statistical
inference a measure of reliability.
There are two such measures, the confidence level and the significance level. The
confidence level is the proportion of times that an estimating procedure will be correct.
When the purpose of the statistical inference is to draw a conclusion about a population,
the significance level measures how frequently the conclusion will be wrong in the long
run.
Statistical inference is the process of making an estimate, prediction, or decision about
a population based on a sample.
What can we infer about a Population's Parameters based on a Sample's Statistics? -
CORRECT ANSWER-Since statistical inference involves using statistics to make
inferences about parameters, we can make an estimate, prediction, or decision about a
population based on sample data. We can apply what we know about a sample to the
larger population from which it was drawn!
Confidence level - CORRECT ANSWER-the proportion of times that an estimating
procedure will be correct. A confidence level of 95% means that estimates based on this
form of statistical inference will be correct 95% of the time.
, significance level - CORRECT ANSWER-measures how frequently the conclusion will
be wrong in the long run. A 5% significance level means that, in the long run, this type
of conclusion will be wrong 5% of the time.
𝛼 - CORRECT ANSWER-Greek letter "alpha"
If we use 𝛼 to represent significance, then our confidence level is 1−𝛼
Confidence Level + Significance Level = 1
Consider a statement from polling data you may hear about in the news: "This poll is
considered accurate within 3.4 percentage points, 19 times out of 20." In this case, our
confidence level is 95% (19/20 = 0.95), while our significance level is 5%. A 5%
significance level means, that in the long run, this type of conclusion will be wrong 5% of
the time.
A company has developed a new smartphone whose average lifetime is unknown. In
order to estimate this average, 200 smartphones are randomly selected from a large
production line and tested; their average lifetime is found to be 5 years. The 200
smartphones represent a - CORRECT ANSWER-sample
Which of the following is a measure of the reliability of a statistical inference -
CORRECT ANSWER-a significance level
The process of using sample statistics to draw conclusions about population parameters
is called - CORRECT ANSWER-doing inferential statistics
Which of the following statements involve descriptive statistics as opposed to inferential
statistics - CORRECT ANSWER-The Alcohol, Tobacco and Firearms Department
reported that Houston had 1,791 registered gun dealers in 1997.
A population of all college applicants exists who have taken the SAT exam in the United
States in the last year. A parameter of the population are - CORRECT ANSWER-SAT
scores
Data - CORRECT ANSWER-Facts and statistics collected together for reference or
analysis
three of the most popular methods to collect data: - CORRECT ANSWER-direct
observation (ex: number of customers entering a bank per hour), experiments (ex: new
ways to produce things to minimize costs), and surveys.
direct observation - CORRECT ANSWER-The simplest method of obtaining data
Another form of descriptive statistics uses numerical techniques to summarize data.
Rather than providing the raw data, the professor may only share summary data with
the student.
Histogram - CORRECT ANSWER-(or bar graph) can show if the data is evenly
distributed across the range of values, if it falls symmetrically from a center peak
(normal distribution), if there is a peak but the more of the data falls on one side of the
peak than the other (a skewed distribution), or if there are two or more peaks in the data
(bi- or multi-modal).
average - CORRECT ANSWER-mean
range - CORRECT ANSWER-calculated by subtracting the smallest number from the
largest.
mode - CORRECT ANSWER-the most frequently occurring score(s) in a distribution
variance - CORRECT ANSWER-the average squared deviation from the mean
What Is Statistics? - CORRECT ANSWER-"Statistics is a way to get information from
data."
Statistics is a tool for creating new understanding from a set of numbers.
You need data and information
descriptive statistics - CORRECT ANSWER-one of two branches of statistics which
focuses on methods of organizing, summarizing, and presenting data in a convenient
and informative way.
One form of descriptive statistics uses graphical techniques which allow statistics
practitioners to present data in ways that make it easy for the reader to extract useful
information.
Standard deviation - CORRECT ANSWER-the square root of the variance and gets the
variability measure back to the same units as the data. Standard deviation has many
useful properties when the data is normally distributed
inferential statistics - CORRECT ANSWER-a body of methods used to draw
conclusions or inferences about characteristics of populations based on sample data.
,Exit polls are a very common application of statistical inference.
Statistical inference problems involve three key concepts: - CORRECT ANSWER-
population, the sample, and the statistical inference.
Population: - CORRECT ANSWER-the group of all items of interest to a statistics
practitioner. It is frequently very large and may, in fact, be infinitely large. In the
language of statistics, population does not necessarily refer to a group of people. It may,
for example, refer to the population of diameters of ball bearings produced at a large
plant.
A descriptive measure of a population is called a parameter. In most applications of
inferential statistics, the parameter represents the information we need.
Sample - CORRECT ANSWER-a set of data drawn from the population. A descriptive
measure of a sample is called a statistic. We use statistics to make inferences about
parameters.
statistical inference - CORRECT ANSWER-the process of making an estimate,
prediction, or decision about a population based on sample data. Because populations
are almost always very large, investigating each member of the population would be
impractical and expensive. It is far easier and cheaper to take a sample from the
population of interest and draw conclusions or make estimates about the population on
the basis of information provided by the sample. However, such conclusions and
estimates are not always going to be correct. For this reason, we build into the statistical
inference a measure of reliability.
There are two such measures, the confidence level and the significance level. The
confidence level is the proportion of times that an estimating procedure will be correct.
When the purpose of the statistical inference is to draw a conclusion about a population,
the significance level measures how frequently the conclusion will be wrong in the long
run.
Statistical inference is the process of making an estimate, prediction, or decision about
a population based on a sample.
What can we infer about a Population's Parameters based on a Sample's Statistics? -
CORRECT ANSWER-Since statistical inference involves using statistics to make
inferences about parameters, we can make an estimate, prediction, or decision about a
population based on sample data. We can apply what we know about a sample to the
larger population from which it was drawn!
Confidence level - CORRECT ANSWER-the proportion of times that an estimating
procedure will be correct. A confidence level of 95% means that estimates based on this
form of statistical inference will be correct 95% of the time.
, significance level - CORRECT ANSWER-measures how frequently the conclusion will
be wrong in the long run. A 5% significance level means that, in the long run, this type
of conclusion will be wrong 5% of the time.
𝛼 - CORRECT ANSWER-Greek letter "alpha"
If we use 𝛼 to represent significance, then our confidence level is 1−𝛼
Confidence Level + Significance Level = 1
Consider a statement from polling data you may hear about in the news: "This poll is
considered accurate within 3.4 percentage points, 19 times out of 20." In this case, our
confidence level is 95% (19/20 = 0.95), while our significance level is 5%. A 5%
significance level means, that in the long run, this type of conclusion will be wrong 5% of
the time.
A company has developed a new smartphone whose average lifetime is unknown. In
order to estimate this average, 200 smartphones are randomly selected from a large
production line and tested; their average lifetime is found to be 5 years. The 200
smartphones represent a - CORRECT ANSWER-sample
Which of the following is a measure of the reliability of a statistical inference -
CORRECT ANSWER-a significance level
The process of using sample statistics to draw conclusions about population parameters
is called - CORRECT ANSWER-doing inferential statistics
Which of the following statements involve descriptive statistics as opposed to inferential
statistics - CORRECT ANSWER-The Alcohol, Tobacco and Firearms Department
reported that Houston had 1,791 registered gun dealers in 1997.
A population of all college applicants exists who have taken the SAT exam in the United
States in the last year. A parameter of the population are - CORRECT ANSWER-SAT
scores
Data - CORRECT ANSWER-Facts and statistics collected together for reference or
analysis
three of the most popular methods to collect data: - CORRECT ANSWER-direct
observation (ex: number of customers entering a bank per hour), experiments (ex: new
ways to produce things to minimize costs), and surveys.
direct observation - CORRECT ANSWER-The simplest method of obtaining data
