BMAL-590 QUANTITATIVE RESEARCH
EXAM QUESTIONS AND ANSWERS.
VERIFIED 2025/2026.
What Is Statistics? - ANS "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 - ANS 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 - ANS (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).
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,average - ANS mean
range - ANS calculated by subtracting the smallest number from the largest.
mode - ANS the most frequently occurring score(s) in a distribution
variance - ANS the average squared deviation from the mean
Standard deviation - ANS 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 - ANS 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: - ANS population, the sample, and
the statistical inference.
Population: - ANS 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 - ANS 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.
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, statistical inference - ANS 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? -
ANS 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 - ANS 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 - ANS 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 - ANS Greek letter "alpha"
If we use 𝛼 to represent significance, then our confidence level is 1−𝛼
Confidence Level + Significance Level = 1
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
EXAM QUESTIONS AND ANSWERS.
VERIFIED 2025/2026.
What Is Statistics? - ANS "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 - ANS 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 - ANS (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).
1 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
,average - ANS mean
range - ANS calculated by subtracting the smallest number from the largest.
mode - ANS the most frequently occurring score(s) in a distribution
variance - ANS the average squared deviation from the mean
Standard deviation - ANS 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 - ANS 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: - ANS population, the sample, and
the statistical inference.
Population: - ANS 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 - ANS 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.
2 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
, statistical inference - ANS 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? -
ANS 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 - ANS 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 - ANS 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 - ANS Greek letter "alpha"
If we use 𝛼 to represent significance, then our confidence level is 1−𝛼
Confidence Level + Significance Level = 1
3 @COPYRIGHT 2025/2026 ALLRIGHTS RESERVED.
