Knewton Alta Lesson 2 Assignment
Which of the following represents the population in the scenario below? A researcher wants to know what percentage of people who live in Germany are satisfied with their government spending. Surveys are sent to people who live in the city limits of Berlin, Frankfurt, and Munich.
People who live in Germany The researcher wants to learn about the satisfaction of all the people in Germany, so this is the population.
Rebecca collected data from a random sample of 500 women from her website asking whether or not they prefer liquid eyeliner or pencil. Based on the results, she reports that 51% of the women in the nation use liquid eyeliner. Why is this statistic misleading?
The sample is biased. The sample in this case is biased. The individuals included in the sample are not representative of the entire population because eyeliners preferred may be different based on different regions or websites used in the country.
The following data set provides information on New York Senate Employees Payroll. If the auditor sampled only the employees working in the capital city of Albany to represent the entire state of New York, what kind of activity has taken place?
Sampling bias Sampling bias takes place when the data analyst does not objectively consider all the data, but instead makes s subjective judgment. The sample from Albany may be quite different than from Rochester.
The following data set provides New York City school based programs cost by borough. Sarah calculated the average tuition fee for the school based programs and announced that Staten Island had the best programs for the least amount. "It is five-hundred thousand dollars under the average cost, and it ranks number 2 out of the 5 boroughs, which is way above average." Why is this statistic misleading?
Her opinion relies on two definitions of the word "average." The statistic for the mean of school based programs is calculated. The phrase "way above average" does not have a statistical meaning.
Raymond wants to estimate the percentage of coworkers that use the company's healthcare. He asks a randomly selected group of 200 coworkers whether or not they use the company's healthcare. What is the data?
specific "yes" or "no" responses to the survey Data is a set of observations. In this case, the data is specific "yes" or "no" responses to the survey.
Which of the following scenarios contains a sampling error? Select the correct answer below: A study is conducted to determine the favorite business area of all the students in your School of Business. Students in your Economics 101 section were used as the sample. A study is conducted about where the best travel destinations are - Europe or Asia. People who live in big cities throughout Europe were used as the sample. A hospital conducts a study about a new heart monitoring software. All patients who use the software were used as the sample. A study is conducted by a cereal manufacturer about two brands of cereal, and a question on a survey read, "Do you prefer the delicious taste of Brand X or the taste of Brand Y?
A study is conducted to determine the favorite business area of all the students in your School of Business. Students in your Economics 101 section were used as the sample.
The following data set provides analysis of the performance of business loans which were identified as being made to a franchise. An investor is offered a partnership deal on a franchise business. She wants to confirm if franchises can succeed by sampling from the over 500 cases measured by the Small Business Administration. If she examines the first 50 rows of their spreadsheet, what kind of sampling is she doing?
Convenience Convenience sampling uses the easiest method of gathering data. It does not have the objectivity of random sampling.
The following data set provides New York City school based programs cost by borough. Jenny expected the school based programs to cost over four million. With that expectation, how many programs would she find in the data that meet this expectation?
Four Four school based programs have costs above $4,000,000.
The following data set provides information on New York Senate Employees Payroll. The auditor decides that the Senate needs feedback about a salary differential between male and female employees. Using everyone's first names, she divides the data into two groups. What kind of activity has taken place?
Sampling bias Sampling bias takes place when the data analyst does not objectively consider all the data, but instead makes a subjective judgment. The auditor has preconceived ideas about the match between gender and first names.
There are four major toothpaste brands: Awesomebrush (A), Brushtastic (B), CheeryBrush (C), and DentalOne (D). A survey of dentists is done which asks which brand they recommend most highly. Which of the following graphs are misleading? Select all correct answers
The first and the third bar graphs are misleading. The first one is misleading because the y-axis is truncated to 20, which makes bar A appear much larger than the other bars. The third pie graph is misleading because it leaves out brands C and D, which distorts A's market share and makes it seem more dominant than it is.
Kenneth collected data from a random sample of 800 voters in his city asking whether or not they would vote to reelect the current governor. Based on the results, he reports that 64% of the voters in his state would vote to reelect the current governor. Why is this statistic misleading?
The sample is biased. The sample in this case is biased. The individuals included in the sample are not representative of the entire population because the voters in his city do not necessarily have the same opinion as the rest of the state.
After asking 9 randomly selected customers from her store if they buy either fresh or frozen produce but not both, Susan reports that 33% of the customers from her store buy fresh produce based on her survey. Why is this statistic misleading? Select the correct answer below: The sample is biased. The data contains an outlier. The sample size is insufficient. The statistic contains a calculation error.
The sample size is insufficient. Although the sampling was random, using such a small sample size to draw conclusions about a much larger number of individuals is bound to be unreliable. This sample size is too small.
A study was conducted to determine whether a new highway should be built next to the river in a town. Half of the residents in the town live near the river. The sample of this study consisted of all the residents in the town who live near the river. Which of the following describes the sampling of this study?
There is sampling bias. Sampling bias exists in this study because the people who live near the river probably have stronger opinions about a new highway being placed next to their homes than the rest of the residents in the town who do not live close to the river.
Is the statement below true or false? A sampling bias is the situation in which not all members of the population are equally likely to be selected. Select the correct answer below: True False
True A sampling bias is defined as the situation in which not all members of the population are equally likely to be selected.
The following data set provides New York City school based programs cost by borough. Ramsesh liked to impress his colleagues with his statistical ability. "Since the mode is $1,188,013, any school based program under that cost is below average." What kind of misleading information is he offering? Select all that apply.
Wrong calculation of the mode. Wrong use of the mode parameter. Ramsesh is confusing the word "mode" with the word "mean," which is the average of the entire population of school based programs in New York City. Both the mean and the mode values for this data set relate to population parameters, not statistics obtained by sampling.
Thomas wants to estimate the mean height of students attending his college. He records the heights of 25 randomly selected students attending the college. What is the parameter?
the mean height of all students attending the college A parameter is a number that is used to represent a population characteristic. In this case, the parameter is the mean height of all students attending the college.
Anna wants to estimate the mean number of siblings for each student in her school. She records the number of siblings for each of 75 randomly selected students in the school. What is the statistic?
the mean number of siblings for the randomly selected students A statistic is a numerical characteristic of the sample. In this case, the statistic is the mean number of siblings for the randomly selected students.
The following data set provides analysis of the performance of business loans which were identified as being made to a franchise. If the investor sorts the list into franchises whose names she recognizes, uses only that data, what kind of sampling is she doing?
Convenience Convenience sampling uses the easiest method of gathering data. It does not have the objectivity of random sampling.
The following data set provides information on New York Senate Employees Payroll. If the auditor was paid by the New York Senate, would her work monitoring them be subject to sampling bias?
No Even if the auditor was paid by the New York Senate, her activity would not constitute sampling bias. She has no control over the numbers in the spreadsheet.
Is the statement below true or false? A nonsampling error is an issue that affects the reliability of sampling data other than natural variation.
True
The following data set provides New York City school based programs cost by borough. Can outliers in the data set influence the data? Can outliers in the data set influence the data?
Yes Outliers are data points that are different from the others; they can influence the mean, which would be misleading if using the mean for comparison studies.
Susan wants to estimate the mean number of ads for each facebook page. She records the number of ads for each of 200 randomly selected facebook pages. What is the population?
all facebook pages The population is the entire group of individuals being studied. In this case, the population is all facebook pages
The following data set provides analysis of the performance of business loans which were identified as being made to a franchise. If the investor groups the franchises by type of food focused upon, and then uses simple random sampling to identify a proportionate number of franchises from each group, what kind of sampling is she doing?
Stratified Stratefied sampling selects a characteristic, such as type of food focused on, to create subpopulations to sample. Stratified sampling includes the steps: divide the population into groups, use simple random sampling to identify a proportionate number of individuals from each group.
The following data set provides information on New York Senate Employees Payroll. Which sampling approach would give the best results for determining the mean salary of RA employees?
Choosing a starting point at random and selecting RA data even spaces apart for at least 30 employees Systematic sampling from option B produces more accurate results than convenience sampling, which is the method described in options A and C. Choice D does not give the mean, unless the data is known to be absolutely symetrical and normally distributed. Systematic sampling includes the steps: list the members of the population, use simple random sampling to select a starting point in the population, let k = (number of individuals in the population)/(number of individuals needed in the sample), choose every kth individual in the list starting with the one that was randomly selected.
The following data set provides New York City school based programs cost by borough. Bryce summarized the report of the school based programs: "The more the cost in programs, the better the school." Is that summary consistent with the data? Select the correct answer below: Yes No
No The data does not show that for every extra dollar spent on a program, the better the school is.
The following data set provides information on New York Senate Employees Payroll. If the auditor added up the contents of the payments, and divided by the number of employees, to get the mean salary, what kind of activity has taken place?
Nonsampling error Non sampling error occurs when the measurement of the data is not correct. The auditor can calculate the mean of the hourly rates of payment for that bi-week. The auditor can calculate the mean of the biweekly rates of payment for the bi-week. However, the auditor cannot calculate the mean salary of the entire group of employees. Other calculations and information would be needed to find the mean salary.
Which of the following scenarios demonstrates sampling bias? Select the correct answer below: To estimate the ethnic background distribution of residents of her regional sales area, Susan collects data from 1000 randomly selected area residents by using a random number generator. Kathryn wants to estimate the mean amount of money spent on clothes per week by mall shoppers. She collects data from every 10th person entering one clothing store at the mall. Brenda wants to estimate the mean amount of money spent per project of engineers at her company. She collects data by recording the amount of money spent per project of every 25th engineer on the list of engineers after a randomly selecting first engineer. To estimate the mean salary of cashiers at his stores, Ryan collects data by recording the salaries of all cashiers included in 12 randomly selected stores.
Kathryn wants to estimate the mean amount of money spent on clothes per week by mall shoppers. She collects data from every 10th person entering one clothing store at the mall. A sample is biased if some individuals of the population are more or less likely to be selected than others. The sample from choice B is biased because mall shoppers that do not visit this particular store are not represented.
The following data set provides information on New York Senate Employees Payroll. The auditor knows the codes for the payment types. TE = Temporary Employee or Hourly Rate, RA = Regular Annual, SA = Special Annual. In looking at the column of data about payments, cell contents range from two to four digits. Is this an example of sampling error?
No Sampling error is not present. The column reports data about employees' payments either biweekly or hourly, and does not distinguish between the two methods of salary determination
Howard collected data from a random sample of 600 people in his department asking whether or not they use the company's healthcare . Based on the results, he reports that 48% of the people in his company use the company's healthcare. Why is this statistic misleading?
The sample is biased. The sample in this case is biased. The individuals included in the sample are not representative of the entire population because the people in his department do not necessarily have the same healthcare as the people in the rest of the company.
The following data set provides New York City school based programs cost by borough. Edward looked at the report of school programs and concluded that 60% of the school programs in New York City cost more than $1,542,952. He used only 10 data points from the whole data set. Why is this statistic misleading?
The sample size is insufficient. A sample size of 10 is insufficient to make a prediction.
After asking 11 randomly selected residents from their town whether or not they own houses, a home rental agency reports that 36% of the residents from their town own houses based on the survey. Why is this statistic misleading? Select the correct answer below: The data contains an outlier. The statistic contains a calculation error. The sample is biased. The sample size is insufficient.
The sample size is insufficient. Although the sampling was random, using such a small sample size to draw conclusions about a much larger number of individuals is bound to be unreliable. This sample size is too small.
After asking 8 randomly selected individuals from her airline whether or not they prefer business or first class, Kathryn reports that 63% of the individuals from her airline prefer business on her airline based on her survey. Why is this statistic misleading?
The sample size is insufficient. Although the sampling was random, using such a small sample size to draw conclusions about a much larger number of individuals is bound to be unreliable. This sample size is too small.
Which of the following scenarios contain nonbiased samples? Select all that apply. Andrea wants to estimate the mean salary of managers at her company. She collects data by recording the salaries of all managers included in 12 randomly selected departments. To estimate the political party distribution of residents in his state, Andrew collects data from a large group of randomly selected residents of his city. Justin wants to estimate the mean profit of stores in his town. He collects data by interviewing members of a candle shop. To estimate the male to female ratio of the residents of his city, Charles collects data by recording the sex of every 50th resident after selecting a random starting point on a list of residents.
Andrea wants to estimate the mean salary of managers at her company. She collects data by recording the salaries of all managers included in 12 randomly selected departments. To estimate the male to female ratio of the residents of his city, Charles collects data by recording the sex of every 50th resident after selecting a random starting point on a list of residents. A sample is biased if some individuals of the population are more or less likely to be selected than others. The sample from choice A is nonbiased because every manager has an equal chance of being selected. The sample from choice D is nonbiased because every resident has an equal chance of being selected.
Which of the following scenarios contain nonbiased samples? Select all that apply: Christine wants to estimate the mean sales of coworkers at her company. She collects data by recording the sales average of every 25th coworker on the list of coworkers after a randomly selecting first coworker. Homer wants to estimate the ethnic background distribution of residents of his regional sales area. He collects data from 1000 randomly selected town residents by using a random number generator. To estimate the mean product use of customers at her XYZ stores, Tammy collects data by selecting a random group of customers from her local XYZ store. To estimate the mean salary of managers at his company, Peter collects data by recording the salaries of all managers included in 12 randomly selected departments.
Christine wants to estimate the mean sales of coworkers at her company. She collects data by recording the sales average of every 25th coworker on the list of coworkers after a randomly selecting first coworker. Homer wants to estimate the ethnic background distribution of residents of his regional sales area. He collects data from 1000 randomly selected town residents by using a random number generator. To estimate the mean salary of managers at his company, Peter collects data by recording the salaries of all managers included in 12 randomly selected departments. A sample is biased if some individuals of the population are more or less likely to be selected than others. The sample from choice A is nonbiased because every coworker has an equal chance of being selected. The sample from choice B is nonbiased because every resident has an equal chance of being selected. The sample from choice D is nonbiased because every manager has an equal chance of being selected.
Select the scenario below that demonstrates sampling bias. Select the correct answer below: Justin wants to estimate the ethnic background distribution of residents of his town. He collects data from 1000 randomly selected town residents by using a random number generator. To estimate the mean salary of accountants at her bank, Patricia collects data by recording the salaries of all accountants included in 12 randomly selected bank sites. Elizabeth wants to estimate the mean vacation days of coworkers at her company. She collects data by selecting a random group of coworkers within her department. To estimate the mean satisfaction level of coworkers at her company, Annie collects data by recording the satisfaction level of every 25th coworker on the list of coworkers after a randomly selecting first coworker.
Elizabeth wants to estimate the mean vacation days of coworkers at her company. She collects data by selecting a random group of coworkers within her department. A sample is biased if some individuals of the population are more or less likely to be selected than others. The sample from choice C is biased because the coworkers in her department only represent one department, which vacation days could be more or less in general than other departments.
The following data set provides the specific sales tax rates for counties in Missouri. A car dealer in Hartville, Missouri, wants to include in marketing materials that customers will pay the lowest sales taxes in Wright County at her dealership. What is the sample?
The city of Hartville, Missouri A sample is a specific subset of the entire group of individuals being studied. In this case, the sample is the city of Hartville, Missouri.
A syringe industry advertises that their average cost for a single syringe is $74. Given that their costs are $11, $84, $94, and $107, why is this statistic misleading?
The data contains an outlier. The average of these costs is accurate, but the advertised average is misleading because so many of the cost are well above this level. The very low cost is an outlier and brings the average down to a misleading value.
In 1936, The Literary Digest conducted a large sample survey of over 2 million Americans to see who they intended to vote for in the presidential election. To identify participants, they used telephone directories, lists of magazine subscribers, and rosters of clubs. 1936 was the middle of the Great Depression; many Americans were unemployed and telephones were a luxury. The Literary Digest predicted that the Republican candidate, Governor Alfred Landon, would get 57% of the vote against Franklin D. Roosevelt's 43%. Is this data misleading? If so, why?
The data is misleading because the sample is biased. The company wanted to survey all Americans, but sampled people who owned telephones, subscribed to magazines, or joined clubs. This is a biased sample, because during the Great Depression, telephones were still a luxury and many people were unemployed. The sample would be biased towards middle- and upper-class Americans. This makes the data and conclusion misleading for the survey the company wanted to conduct.
After asking 9 randomly selected students from her school whether or not they get at least 8 hours of sleep each night , Stephanie reports that 33% of the students from her school get at least 8 hours of sleep each night based on her survey. Why is this statistic misleading?
The sample size is insufficient. Although the sampling was random, using such a small sample size to draw conclusions about a much larger number of individuals is bound to be unreliable. This sample size is too small.
Select all of the following scenarios below that contain nonbiased samples. Select all that apply: To estimate the age distribution of customers at his stores, Frank collects data from a large group of randomly selected customers of his local store. To estimate the mean number of days to ship products at his company, Samuel collects data from a randomly selected proportionate number of shipments from each company site. David wants to estimate the mean returns of products at his website. He collects data by recording the returns of every 25th product on the list of products after a randomly selecting first product. Helen wants to estimate the male to female ratio of the customers of her stores. She collects data by recording the sex of every 50th customer after selecting a random starting point on a list of customers.
To estimate the mean number of days to ship products at his company, Samuel collects data from a randomly selected proportionate number of shipments from each company site. David wants to estimate the mean returns of products at his website. He collects data by recording the returns of every 25th product on the list of products after a randomly selecting first product. Helen wants to estimate the male to female ratio of the customers of her stores. She collects data by recording the sex of every 50th customer after selecting a random starting point on a list of customers. A sample is biased if some individuals of the population are more or less likely to be selected than others. The sample from choice B is nonbiased because every shipment has an equal chance of being selected. The sample from choice C is nonbiased because every product has an equal chance of being selected. The sample from choice D is nonbiased because every customer has an equal chance of being selected.
Which of the following scenarios contain biased samples? Select all that apply. To estimate the mean project completions of technicians in his company, Donald collects data by recording completions from the warehouse area. Kenneth wants to estimate the mean market shares of his company. He collects data by selecting a random group of coworkers within one department. To estimate the male to female ratio of the residents of her city, Janice collects data by recording the sex of every 50th resident after selecting a random starting point on a list of residents. Amy wants to estimate the mean accidents of coworkers at her company. She collects data by recording the accidents of every 25th coworker on the list of coworkers after a randomly selecting first coworker.
To estimate the mean project completions of technicians in his company, Donald collects data by recording completions from the warehouse area. Kenneth wants to estimate the mean market shares of his company. He collects data by selecting a random group of coworkers within one department. A sample is biased if some individuals of the population are more or less likely to be selected than others. The sample from choice A is biased because completions in the warehouse area will be different than the other areas/departments. The sample from choice B is biased because the market shares only represent one department and all other coworkers do not have an equal chance of selection to represent all sales in the company.
Which of the following is most likely an example of a non-sampling error? Select all correct answers. Two researchers randomly sample moviegoers to find their preferred movie snack. They use the same methods to randomly select moviegoers and record their information. The first researcher finds that 45% prefer popcorn, but the second researcher finds that 51% prefer popcorn. Two researchers distribute paper questionnaires to find out which of several candidates for city council is preferred before the election. The first researcher realizes later that several of the questionnaires he distributed had misprinted and left off one of the candidates. Two researchers create an online poll to find out whether people primarily use a computer, a smartphone, or a tablet to surf the web. After collecting their data, they realize that a bug made it harder for people with a smartphone to submit a response to the survey.
Two researchers distribute paper questionnaires to find out which of several candidates for city council is preferred before the election. The first researcher realizes later that several of the questionnaires he distributed had misprinted and left off one of the candidates. Two researchers create an online poll to find out whether people primarily use a computer, a smartphone, or a tablet to surf the web. After collecting their data, they realize that a bug made it harder for people with a smartphone to submit a response to the survey. Because the methods the researchers used were the same, the difference in their statistics is likely due to sampling error. So this is most likely not a non-sampling error.
There are more people who volunteer in soup kitchens in the state of California than in the state of Arizona. Therefore, the people of the state of California are more willing to volunteer their time than the people of Arizona. Is there a problem with this logic? Explain. Select the correct answer below: Yes, there is a problem with the logic. More people in California live by a beach, and are therefore more willing to volunteer than those people in Arizona. Yes, there is a problem with the logic. California has more residents than Arizona, therefore there is a likelihood that there will be more volunteers in soup kitchens as well. No, there is not a problem with the logic. The number of volunteers in California is greater than in Arizona, which means that people in California are more likely to volunteer in soup kitchens than people in Arizona. No, there is not a problem with the logic. There are more soup kitchens in the state of California, so there will be more volunteers.
Yes, there is a problem with the logic. California has more residents than Arizona, therefore there is a likelihood that there will be more volunteers in soup kitchens as well. The flat number of volunteers is likely proportional to the number of residents a state has. California is a larger state than Arizona and contains more people, so it is highly likely that it will also have more volunteers. However, in general, this does not mean that all people in the state of California are more willing to volunteer than those in Arizona.
In order to study the mean video views of people on his website, Richard samples the population by dividing the viewers by age and randomly selecting a proportionate number of viewers from each age group. Which type of sampling is used?
stratified sampling This scenario demonstrates stratified sampling. Stratified sampling involves dividing the population into groups and randomly selecting a proportionate number of individuals from each group.
A sampling bias is _______.
the situation in which not all members of the population are equally likely to be selected A sampling bias is defined as the situation in which not all members of the population are equally likely to be selected.