Sta- 2023 Chapter 1
Exam Questions and
Complete Solutions
Graded A+
Statistics - Answer: The science of collecting, organizing, summarizing analyzing info to draw conclusions
or answer questions. In addition, statistics is about providing a measure of confidence in any conclusions
Data - Answer: Fact or proposition used to draw a conclusion or make a decision. Data describes
characteristics of an individual. Data varies
True/ False
In statistics, results are always reported with 100% certainty. - Answer: False. In statistics, results are not
reported with 100% certainty. because statistical studies draw on samples, and because there is
variation within groups, results cannot be reported with 100% certainty
True/False
Statistical studies are not concerned with understanding the sources of variability in data, only with
describing the variability in the data. Choose the correct answer below. - Answer: False. Statistical
studies are concerned with both describing the variability in the data and understanding the sources of
variability in data. Understanding the sources allows researchers to control it and reach better
conclusions.
True/False
Suppose three different individuals conduct the same statistical study, such as estimating the average
commute time of students at a college. It is possible that all three students end up with different results.
Choose the correct answer - Answer: True. Statistical studies typically look at samples rather than entire
populations. Since each study is likely to draw different samples, it is quite possible that each study ends
up with different results, due to variability in the data
,Population - Answer: the entire group of individuals or instances about whom we hope to learn or study
Sample - Answer: a subset of the population being studied
Individual - Answer: is a person or object that is a member of the population being studied
descriptive statistics - Answer: consist of organizing and summarizing data. It describes data through
numerical summaries, tables and graphs
Statistic - Answer: a numerical summary of a sample
inferential statistics - Answer: uses methods that take a result from a sample, extend it to the
population, and measure the reliability of the result- Always include a level of confidence in the results,
it also includes a range of values
Ex: We are 95% confident that between 76% and 84% of all students would return the money
Parameter - Answer: A numerical summary of population
Ex: Suppose the percentage of all students on your campus who own a car is 48%. This value represents
a parameter because it is a numerical summary of a population
Statistic - Answer: A statistic is a numerical summary of a sample
Ex: Suppose a sample of 100 students is obtained and from this sample we find that 46% own a car. This
value represents a statistic because it is a numerical summary of a sample
Variable - Answer: The characteristic of individuals in a study. Variables vary. If they didn't, variables
with be constants and inferential statistics would not be necessary
, Ex: Recently, my son and I planted a tomato plant in our backyard. We were interested in studying the
weights (the variable) of each tomato (the individual)
Goal of research - Answer: To learn the causes of variability
Ex: By researching the variable, we hope to learn to grow plants that yield the best tomatoes. That is,
why do some tomatoes weigh more than others?
Variables are classified in two groups - Answer: Qualitative and Quantitive
Qualitative or categorical - Answer: variables allow for classification of individuals based on some
attribute or characteristic
Quantiative variables - Answer: provide numerical measures of individuals. The values of a quantitive
variable can be added or subtracted and provide meaningful results
Ex: The Variable (weight of a tomato) is quantitative because the values of the variable (the weights)
provide numerical measures of the individuals (the tomatoes). If you subtract the weight of one small
tomato from the weight of a larger one, it would provide a meaningful number telling how much heavier
the large tomato was, compared with the smaller one.
Examples of Qualitative variables - Answer: Gender - male/female
Zip code - can't add, nor subtract and come up with a meaningful result
examples of quantitative variables - Answer: A numerical value doesn't automatically suggest a variable
is quantitative
Temperature - changes
Number of days college student studies - can change
Exam Questions and
Complete Solutions
Graded A+
Statistics - Answer: The science of collecting, organizing, summarizing analyzing info to draw conclusions
or answer questions. In addition, statistics is about providing a measure of confidence in any conclusions
Data - Answer: Fact or proposition used to draw a conclusion or make a decision. Data describes
characteristics of an individual. Data varies
True/ False
In statistics, results are always reported with 100% certainty. - Answer: False. In statistics, results are not
reported with 100% certainty. because statistical studies draw on samples, and because there is
variation within groups, results cannot be reported with 100% certainty
True/False
Statistical studies are not concerned with understanding the sources of variability in data, only with
describing the variability in the data. Choose the correct answer below. - Answer: False. Statistical
studies are concerned with both describing the variability in the data and understanding the sources of
variability in data. Understanding the sources allows researchers to control it and reach better
conclusions.
True/False
Suppose three different individuals conduct the same statistical study, such as estimating the average
commute time of students at a college. It is possible that all three students end up with different results.
Choose the correct answer - Answer: True. Statistical studies typically look at samples rather than entire
populations. Since each study is likely to draw different samples, it is quite possible that each study ends
up with different results, due to variability in the data
,Population - Answer: the entire group of individuals or instances about whom we hope to learn or study
Sample - Answer: a subset of the population being studied
Individual - Answer: is a person or object that is a member of the population being studied
descriptive statistics - Answer: consist of organizing and summarizing data. It describes data through
numerical summaries, tables and graphs
Statistic - Answer: a numerical summary of a sample
inferential statistics - Answer: uses methods that take a result from a sample, extend it to the
population, and measure the reliability of the result- Always include a level of confidence in the results,
it also includes a range of values
Ex: We are 95% confident that between 76% and 84% of all students would return the money
Parameter - Answer: A numerical summary of population
Ex: Suppose the percentage of all students on your campus who own a car is 48%. This value represents
a parameter because it is a numerical summary of a population
Statistic - Answer: A statistic is a numerical summary of a sample
Ex: Suppose a sample of 100 students is obtained and from this sample we find that 46% own a car. This
value represents a statistic because it is a numerical summary of a sample
Variable - Answer: The characteristic of individuals in a study. Variables vary. If they didn't, variables
with be constants and inferential statistics would not be necessary
, Ex: Recently, my son and I planted a tomato plant in our backyard. We were interested in studying the
weights (the variable) of each tomato (the individual)
Goal of research - Answer: To learn the causes of variability
Ex: By researching the variable, we hope to learn to grow plants that yield the best tomatoes. That is,
why do some tomatoes weigh more than others?
Variables are classified in two groups - Answer: Qualitative and Quantitive
Qualitative or categorical - Answer: variables allow for classification of individuals based on some
attribute or characteristic
Quantiative variables - Answer: provide numerical measures of individuals. The values of a quantitive
variable can be added or subtracted and provide meaningful results
Ex: The Variable (weight of a tomato) is quantitative because the values of the variable (the weights)
provide numerical measures of the individuals (the tomatoes). If you subtract the weight of one small
tomato from the weight of a larger one, it would provide a meaningful number telling how much heavier
the large tomato was, compared with the smaller one.
Examples of Qualitative variables - Answer: Gender - male/female
Zip code - can't add, nor subtract and come up with a meaningful result
examples of quantitative variables - Answer: A numerical value doesn't automatically suggest a variable
is quantitative
Temperature - changes
Number of days college student studies - can change
