Twenty Questions Subject:

Twenty Questions

1. A sample of 500 employees of a company is selected and the average height is found to be 5ft 9in. Is this figure a statistic or a parameter? This is a statistic because it is representative of the sample.

2.The amount of milk produced by a cow in a given day would be considered discrete or continuous data? The amount is considered continuous because the amount of milk, depending upon when measured, could be a non-countable number.

3. Shirt sized of small, medium and large would be considered nominal, ordinal, interval or ratio? The sizes would be ordinal because we can put them in a ranked order but can’t find a numerical difference between any.

4. Heights of the basketball team would be nominal, ordinal, interval, or ratio? Heights would be ratio because there is a natural zero (no height at all), the numbers can be put in order from least to greatest, and the differences between the numbers mean something.

5. The counties of Arkansas would be nominal, ordinal interval or ratio? The counties would be nominal because there is no way to rank the counties or find a difference between two.

6. Jan randomly asks 50 employees of Sure Tan about their favorite tanning lotion. Identify the sample, population, and if the sample would be representative of the population. The sample is the 50 employees polled, the population is all the employees of Sure Tan and the sample is likely to be representative because it is a good size sample and was collected randomly.

7. Give an alternative conclusion to the following situation: A study shows that adults who work at their desk all day weigh more than those who do not. Conclusion: Desk jobs cause people to gain weight. People who sit at a desk all day are less active than those who do not, therefore their lack of exercise may cause them to gain weight, not the job itself.

8. A researcher published this survey result: “74% of people would be willing to spend 10% more for energy from a non-polluting source”. The survey question was announced on a national radio show and 1200 listeners responded by calling in. What is wrong with this survey? The survey is not random therefore has serious potential for a bias result to be produced.

9. A T.V. show’s executives commissioned a study to gauge the impact of the show’s ratings on the sales of its advertisers. Is this an experiment or observational study? This is an observational study because the people were not asked to alter their regular behavior in any way in order to participate.

10.A doctor performs several diagnostic tests to determine the reason for a patient’s illness. Is this an experiment or observational study? This would be an experiment because the patient has to participate not just be observed.

11.Researchers collect data by interviewing survivors of the holocaust. Is this cross-sectional, retrospective, or prospective? This would be retrospective because they are collecting data about the past.

12. An officer gathers data about a wreck on 167 this morning in order to issue citations at the scene. Is this cross-sectional, retrospective, or prospective? This is cross sectional because the data is being collected at the time of the accident.

13. A tax auditor selects every 100 th income tax return that is received the inspect for errors. Is this a random, systematic, stratified, convenience or cluster sample? This is systematic because he has a system of collecting the data that he is following.

14. A pollster uses a computer to generate 500 random numbers, then calls the people associated with each number. Is this a random, systematic, stratified, convenience or cluster sample? This is a random sample.

15. The government is interested in the sports participated in by high schools across the country. They have each state conduct a survey of their residents and send the results back to Washington. Would they need to use a random, systematic, stratified, convenience or cluster sample? They should use a cluster sample because the population is very large and cluster samples are cost and time efficient to gather.

16.To avoid working late, a quality control analyst simply inspects the first 100 items produced in a day. Is this a random, systematic, stratified, convenience or cluster sample? This is a convenience sample because the worker chooses a sample that is easy for him to collect.

17. If three of the classes in a frequency table are 2-15, and , what is the width of each class? The width of each class is 14.

18. If and are two classes of a frequency distribution, find the class boundaries for a class of The boundaries would be and

19. There are 100 pieces of data collected and arranged in a frequency distribution. In the class of there was a frequency of 25. What would be the relative frequency of that class? The relative frequency would be 25% or 25/100.

20. Suppose a data set has 60 pieces of data with 100 and 20 being your max and min values. If you wanted 8 classes, and 20 to be the lower boundary of your first class, how big should you make your class width? The class width should be 11 so that you are sure to include 100 in the last class