BMAL-590 Quantitative Research Exam Questions and
Answers Grade A+
What Is Statistics? - 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 - 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.
,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 - 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 - Answer-mean
range - Answer-calculated by subtracting the smallest number from the largest.
mode - Answer-the most frequently occurring score(s) in a distribution
variance - Answer-the average squared deviation from the mean
Standard deviation - 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 - 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: - Answer-population, the
sample, and the statistical inference.
Population: - 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 - 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 - 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?
- 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 - 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.
Answers Grade A+
What Is Statistics? - 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 - 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.
,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 - 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 - Answer-mean
range - Answer-calculated by subtracting the smallest number from the largest.
mode - Answer-the most frequently occurring score(s) in a distribution
variance - Answer-the average squared deviation from the mean
Standard deviation - 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 - 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: - Answer-population, the
sample, and the statistical inference.
Population: - 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 - 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 - 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?
- 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 - 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.
