Devry MATH221 Week 8 Quiz Latest 2021 June

MATH221 Statistics for Decision Making

Week 8 Quiz

Question 1If neighbors wanted to have a speed bump installed on one part of the road, which statistical method would be most effective.

  Regression with speed as the dependent variable

  Hypothesis testing with a null hypothesis that the speed is less than or equal to the posted speed

  Hypothesis testing with a null hypothesis that the speed is more than the posted speed

  Use a confidence interval with the posted speed as the mean

  Regression with speed as an independent variable

 Question 2If a franchise company wanted to determine why sales were higher at some locations rather than others, what statistical process would be most appropriate?

  Use a confidence interval with the posted speed as the mean

  Regression with sales as the dependent variable

  Hypothesis testing with a null hypothesis that the sales are less than or equal to the highest sales

  Regression with sales as an independent variable

  Hypothesis testing with a null hypothesis that the sales are more than the highest sales

 Question 3A coffee shop fills its 10 fluid ounce cups, but tries to come up a bit short so that customers don’t spill hot coffee on themselves.  The cups are sold as having 9.5 fluid ounces.  What statistical strategy would allow them to see if this method is being implemented correctly?

  A hypothesis test with an alternative hypothesis that is less than 10 fluid ounces

  A hypothesis test with an alternative hypothesis that is less than 9.5 fluid ounces

  A confidence interval with 10 fluid ounces as the mean

  A hypothesis test with an alternative hypothesis that is more than 9.5 fluid ounces

  A hypothesis test with an alternative hypothesis that is more than 10 fluid ounces

 Question 4A teacher wants to track the number of books students have read each week, encouraging them to increase their reading throughout the school year.  Which of the following graphs might be most effective to inspire the student?

  A week-by-week pie chart

  A new scatter plot each week with each student on the x axis and number of books on the y axis

  A time series graph with the weeks on the x axis and number of books on the y axis

  A time series graph with each student on the x axis and attendance on the y axis

  A Pareto chart showing the week with the most books read to the week with the least books read

 Question 5A TV reporter is looking at polling for the coming presidential election. He wants to determine if the polling shows that one candidate or the other has a true lead on the other candidate.  Which statistical method would help determine if one candidate has a true lead in the election?

  Find a confidence interval for each candidate’s poll results and check that they do not overlap

  Regression with poll results as the independent variable

  Use a confidence interval based on last year's polling results

  Regression with poll results as the dependent variable

  Compare the sample mean of each

 Question 6 A baseball manager is looking to examine the distribution of batting averages for his team to see if they are performing up to expectations as a team.  The most effective graph to show this distribution would be:

  A box and whisker plot

  A histogram

  A pie chart

  A scatter plot

  A Pareto chart

 Question 7When looking at poll results in the newspaper, one outcome is fairly close to the other.  What statistical strategy would help determine if these values are essentially equal?

  Use a confidence interval of pass polls on this same issue

  Hypothesis testing with a null hypothesis that one poll result is less than the other

  Regression with poll results as an independent variable

  Use a confidence interval for each result to see if they overlap

  Regression with poll results as the dependent variable

 Question 8The CDC wants to determine why COVID-19 infection rates are lower in some states than in others. What statistical method would be most appropriate?

  A confidence Interval with the expected number of infections per state as the mean

  A regression with the infection rate as the dependent variable

  A hypothesis test with a null hypothesis that the infection rate is greater than or equal to the expected number

  A hypothesis test with a null hypothesis that the infection rate is less than or equal to the expected number

  A regression with the infection rate as the independent variable

 Question 9A real estate company is asking the likelihood that a house in a specific neighborhood will sell within 14 days on the market.  Which statistical process would be helpful in making an informed estimate?

  Determine the probability that other houses sold in that neighborhood in exactly 14 days

  Determine the probability that other houses sold in that neighborhood in less than or equal to 14 days

  Determine the probability that other houses sold in that neighborhood in less than or equal to 15 days

  A regression analysis with days on the market until being sold as an independent variable

  Determine the probability that other houses sold in the United States in exactly 14 days

 Question 10A toaster company wants to provide a warranty for its toasters, and is willing to replace about 5% of those sold each year.  What type of calculation would help in determining the most appropriate warranty time to offer customers?

  A frequency distribution of the defective toasters each year

  A pie chart of the possible percentage of defective toasters each year

  A normal distribution calculation for the years a toaster should last

  A binomial probability calculation for defective toasters

  An inverse normal distribution calculation from 5% to number of years

 Question 11Match the best answer on the right to the item on the left.

Average of all values in the data set

Most frequently occurring value in the date set

Exact middle of the data set

Data that is words only and cannot be ranked

Data that can be ranked

Data where the difference between data values has meaning but there is no defined starting point

Data where there is a defined starting point or zero and the ratios of data values has meaning

Data is collected from every member of the population

Data is collected from a subset of the population

Data is collected by watching the behavior of sample

Data is collected by imposing a treatment on a sample and examining the results

Data is collected as a result of computer modeling

Data is collected by asking a series of questions

Data is collected that does not fairly represent the population

A measure of the spread or variability of the data set

r

μ

x?, x?, x?

Question 12Which of the following survey results are most likely to include a bias due to sampling?

  Phone survey done by university of alumni to represent opinion of alumni

  Poll taken by visitors of political organization website to estimate future election results

  Mail survey to those who purchased a product from that company to determine customer satisfaction

  Customer comment card responses at a restaurant regarding their service

  Survey by Gallop organization of 1000 random US adults to represent US population

 Question 13When betting whether a coin will land on heads, you find that the coin has landed on tails the last four flips.  Assuming this is a fair coin, should you increase the amount of your bet of landing on heads for the fifth flip?

  Yes, on a fair coin, heads will be more likely

  No, tails is more likely on a fair coin

  Yes, as after four tails, a head is more likely the next outcome

  No, the probabilities do not change based on previous flips

  No, you should bet on tails given those previous results

 Question 14To study the interest in sports of junior high kids, an organization focused on those kids being most active during the outside time of the day.  Would you expect the results to be biased?  Why or why not?

  No, as inactive kids likely feel the same as the active kids

  Yes, as inactive kids may have different opinions from the others

  No, sports are universally of interest

  No, all active kids would be equally eligible to be in the sample

  Yes, the wording of the questions might push kids to a specific answer

 Question 15Which of the following organizations (not all are real, consider only the name) is most likely to provide the least biased results of a study on the regulation of fireworks in a specific state.

  Organization of nationwide 4th of July celebrations

  Hospital ER organization

  State government organization

  Pet lover’s organizations

  Firework manufacturing association

 Question 16Imagine you read poll results that found that 49% of individuals liked buying food at movies, while 42% of individuals did not like buying food at movies.  This poll had an error of +/- 4%.  Based on this result, can one say that in the population, more people like buying food at the movies?

  No, as the poll results show most people do not like to buy food at the movies

  Yes, as that had the higher percentage in the poll

  No, as polls cannot reflect the population

  Yes, as that would be considered common knowledge

  No, as the results are within the margin of error