STATISTICS. Write the word or phrase that best completes each statement

SHORT ANSWER.

Write the word or phrase that best completes each statement or answers the question.  Use critical thinking to determine whether the sampling method appears to be sound or is flawed. 1) An airline company advertises that 100% of their flights are on time after checking 5 1)  randomly selected flights and finding that these 5 were on time. What is wrong with their   claim?  Provide an appropriate response.  2) A market researcher obtains a sample of 50 people by standing outside a store and asking 2)  every 20th person who enters the store to fill out a survey until she has 50 people. What   sampling method is being used here? Will the resulting sample be a random sample? Will it be a simple random sample? Explain your thinking.  Use critical thinking to determine whether the sampling method appears to be sound or is flawed. 3) "7 out of 10 dentists recommend Brand X toothpaste". This finding is based on the results of 3)  a survey of 10 randomly selected dentists. What is wrong with this survey?  4) "38% of adults in the United States regularly visit a doctor". This conclusion was reached 4)  by a college student after she had questioned 520 randomly selected members of her   college. What is wrong with her survey?  Provide an appropriate response.  5) At a school there are two different math classes of the same age. The two classes have 5)  different teachers. The school principal is interested in gauging the effectiveness of two   different teaching methods and asks each teacher to try one of the methods. At the end of   the semester both classes are given the same test and the results are compared. In this   experiment, what is the variable of interest? Give some examples of variables which could   be confounding variables.  6) In a clinical trial for a new headache medication, participants are randomly assigned to a 6)  treatment group or a placebo group. They do not know whether they are receiving the   medication or a placebo. However the doctors administering the medication and   evaluating the results do know which participants are receiving the medication. This   experiment is blind but not double blind. Explain what this means and why the absence of   double blinding could cause a problem.  7) Explain in your own words why a bar graph can be misleading if one or both of the scales 7)  begin at some value other than zero.  
1 8) Describe any similarities or differences in the two distributions represented by the 8) following boxplots. Assume the two boxplots have the same scale.     Find the mean and median for each of the two samples, then compare the two sets of results. 9) A comparison is made between summer electric bills of those who have central air and 9)     those who have window units.          May June July Aug Sept              Central $32 $64 $80 $90 $65       Window $15 $84 $99 $120 $40      Solve the problem.          10) The mean salary of the female employees of one company is $29,525. The mean salary of 10)    the male employees of the same company is $33,470. Can the mean salary of all employees      of the company be obtained by finding the mean of $29,525 and $33,470? Explain your      thinking. Under what conditions would the mean of $29,525 and $33,470 yield the mean      salary of all employees of the company?     Provide an appropriate response.         11) Boxplots are graphs that are useful for revealing central tendency, the spread of the data, 11)    the distribution of the data and the presence of outliers. Draw an example of a box plot and      comment on each of these characteristics as shown by your boxplot.      12) The graph below shows the number of car accidents occurring in one city in each of the 12) years 2001 through 2006. The number of accidents dropped in 2003 after a new speed limit was imposed. Does the graph distort the data? How would you redesign the graph to be less misleading?  
13) The graph below shows the average cost of renting a studio in one city in each of the years 13) 2002 through 2006. By what percentage does the average price increase from 2002 to 2003? Obtain a second version of the graph by sliding a piece of paper over the bottom of the graph so that the bars start at 300. In this new graph, by what percentage does the price appear to increase from 2002 to 2003? Is the second graph misleading?   3 MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.  Construct a modified boxplot for the data. Identify any outliers. 14) The weights (in ounces) of 27 tomatoes are listed below. 14) 1.7 2.0 2.2 2.2 2.4 2.5 2.5 2.5 2.6  2.6 2.6 2.7 2.7 2.7 2.8 2.8 2.8 2.9  2.9 2.9 3.0 3.0 3.1 3.1 3.3 3.6 4.2