EXST 2201 EXAM 2 QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS VERIFIED GRADED ++
[know] To make an important decision in life, we want to know what type of
information from statistics?
population information
Why does the population contain more information than a sample?
population has more data values.
Why does more data values contain more information?
Using more data values in the statistics gives a better idea of all the data values in the
population.
Select all steps used in the process to do statistical inference.
.Theorize - Probability information from a theoretical study of the population.
Analyze - Sample information from a column of data values.
Infer - Population Information using a confidence interval or a hypothesis test.
What type of statistics is used to get sample information?
descriptive statistics because they describe the sample
What type of statistics is used to get population information?
inferintal statistics because they infer the population values
Why is knowing the value of the population mean important?
bc it gives one data value that is in middle of all data values.
Please select one answer in response to the statement: "We can never know the
true value of a population mean".
,true because we can never see an entire population to do the calculation
If knowing any one value in a column of data values, why is knowing the value of
the population mean important?
bc in the normal dist most of the data values are clustered close to the mean
Why is the sample average important in statistics?
bc its the best sample estimator for the mean
Please select all steps in the General Method for Solving Problems in Statistics.
Step A: Abstract problem information.
Step 1: Theorize probability information.
Step 2: Analyze sample information.
Step 3: Infer population information.
please select what is NOT the purpose of the Process of Abstraction?
to see how the situation fits into the field of stats.
A 30-year-old veterinarian wanted to know if the puppies born in her clinic
weighed less than 0.5 pounds on average. So, she weighed 25 puppies and found
a sample average weight of 0.55 pounds.
0.5 = μ (pop. mean) 25 = n (sample #) 0.55 = x̄ (sample mean)
Please abstract the situation below by matching the symbols with their
appropriate numbers.
An engineer was responsible for 5 machines making ball bearings that were
supposed to be 1.2 cm in diameter with standard deviation of 0.01 cm. He
suspected that one of the machines was making too small ball bearings, so he
,measured 37 ball bearings from this machine and found an average diameter of
1.15 cm with a standard deviation of 0.015 cm.
1.15 = x̄ 0.01 = σ 1.15 = s1 .2 = μ
Zillow lists the average home price in our area as $215,816 with a standard
deviation of $21,500. To find out if this was still true, a real estate professional
collected the data for 58 recently sold homes and found an average of $235,000
with a standard deviation of $23,500.
215,816 = μ (population mean)23,500 = s (sample standard deviation)21,500 = σ
(population standard deviation)235,000 = x̄ (sample mean)
What are the major tools used in the Theorize step?
schematic curve, probability table and transformation equation.
What occurs in the Analyze step?
the calculations for the method chosen
What occurs in the Infer step?
Inferring a population value from a sample value.
Please select an appropriate end result for the following two steps of the General
Method for Solving Problems in Statistics.
theorize step- a t-value coming from probability
analyze step- a t value coming from the sample
Please select the two most important inferential statistical methods.
Confidence intervals.
Hypothesis tests.
, In the process of inference, please select the most appropriate answer to the
questions below.
What is a sample average?
What is a confidence interval?.
Sample average = A point estimate of the population mean
Confidence interval = An interval estimate of the population mean
Please select how often the statistics below capture the value of the population
mean.
sample avg-almost neva
confidence int- an interval estimate of the pop mean
What value is in the middle of a confidence interval?
The value of the sample average
Why does the field of statistics need the method of confidence intervals?
Because we have uncertain data and the population mean cannot be known
What prior knowledge is the logic of a confidence interval based on?
The sample dist of the sample average
Is the interval below a proper denotation of a confidence interval?
no bc the values in the parentheses must go from highest to lowest to highest
Please match each summary number with what information probability can add.
Sample average (x̄) = A range of likely values for the population mean
Population mean (μ) = A range of likely values for the sample average
The confidence limits in a confidence interval are just the x-values of a middle
body area in the schematic curve.
COMPLETE SOLUTIONS VERIFIED GRADED ++
[know] To make an important decision in life, we want to know what type of
information from statistics?
population information
Why does the population contain more information than a sample?
population has more data values.
Why does more data values contain more information?
Using more data values in the statistics gives a better idea of all the data values in the
population.
Select all steps used in the process to do statistical inference.
.Theorize - Probability information from a theoretical study of the population.
Analyze - Sample information from a column of data values.
Infer - Population Information using a confidence interval or a hypothesis test.
What type of statistics is used to get sample information?
descriptive statistics because they describe the sample
What type of statistics is used to get population information?
inferintal statistics because they infer the population values
Why is knowing the value of the population mean important?
bc it gives one data value that is in middle of all data values.
Please select one answer in response to the statement: "We can never know the
true value of a population mean".
,true because we can never see an entire population to do the calculation
If knowing any one value in a column of data values, why is knowing the value of
the population mean important?
bc in the normal dist most of the data values are clustered close to the mean
Why is the sample average important in statistics?
bc its the best sample estimator for the mean
Please select all steps in the General Method for Solving Problems in Statistics.
Step A: Abstract problem information.
Step 1: Theorize probability information.
Step 2: Analyze sample information.
Step 3: Infer population information.
please select what is NOT the purpose of the Process of Abstraction?
to see how the situation fits into the field of stats.
A 30-year-old veterinarian wanted to know if the puppies born in her clinic
weighed less than 0.5 pounds on average. So, she weighed 25 puppies and found
a sample average weight of 0.55 pounds.
0.5 = μ (pop. mean) 25 = n (sample #) 0.55 = x̄ (sample mean)
Please abstract the situation below by matching the symbols with their
appropriate numbers.
An engineer was responsible for 5 machines making ball bearings that were
supposed to be 1.2 cm in diameter with standard deviation of 0.01 cm. He
suspected that one of the machines was making too small ball bearings, so he
,measured 37 ball bearings from this machine and found an average diameter of
1.15 cm with a standard deviation of 0.015 cm.
1.15 = x̄ 0.01 = σ 1.15 = s1 .2 = μ
Zillow lists the average home price in our area as $215,816 with a standard
deviation of $21,500. To find out if this was still true, a real estate professional
collected the data for 58 recently sold homes and found an average of $235,000
with a standard deviation of $23,500.
215,816 = μ (population mean)23,500 = s (sample standard deviation)21,500 = σ
(population standard deviation)235,000 = x̄ (sample mean)
What are the major tools used in the Theorize step?
schematic curve, probability table and transformation equation.
What occurs in the Analyze step?
the calculations for the method chosen
What occurs in the Infer step?
Inferring a population value from a sample value.
Please select an appropriate end result for the following two steps of the General
Method for Solving Problems in Statistics.
theorize step- a t-value coming from probability
analyze step- a t value coming from the sample
Please select the two most important inferential statistical methods.
Confidence intervals.
Hypothesis tests.
, In the process of inference, please select the most appropriate answer to the
questions below.
What is a sample average?
What is a confidence interval?.
Sample average = A point estimate of the population mean
Confidence interval = An interval estimate of the population mean
Please select how often the statistics below capture the value of the population
mean.
sample avg-almost neva
confidence int- an interval estimate of the pop mean
What value is in the middle of a confidence interval?
The value of the sample average
Why does the field of statistics need the method of confidence intervals?
Because we have uncertain data and the population mean cannot be known
What prior knowledge is the logic of a confidence interval based on?
The sample dist of the sample average
Is the interval below a proper denotation of a confidence interval?
no bc the values in the parentheses must go from highest to lowest to highest
Please match each summary number with what information probability can add.
Sample average (x̄) = A range of likely values for the population mean
Population mean (μ) = A range of likely values for the sample average
The confidence limits in a confidence interval are just the x-values of a middle
body area in the schematic curve.
