Q&A Hero

Q: The following class limits would be acceptable for developing a frequency distribution on income: $0 < $5,000 $5001 < $10,000 $10,001 < $20,000 Over $20,000

Q: The upper and lower limits of each class in a frequency distribution are also referred to as the data array.

Q: There is no hard-and-fast rule regarding the number of classes that must be used when establishing a frequency distribution for a continuous variable.

Q: Once you have determined the class width using the formula, high-low divided by the number of classes, it is appropriate to round to the nearest integer to make the analysis easier.

Q: The appropriate number of classes should generally be between 5 and 20.

Q: In constructing a frequency distribution for the savings account balances for customers at a bank, the following class boundaries might be acceptable if the minimum balance is $5.00 and the maximum balance is $18,700: $0.00 - $5,000 $5,000 - 10,000 $10,000 - $15,000 $15,000 - $20,000

Q: A cumulative frequency distribution shows the percentage of observations for the variable of interest with values less than or equal to the upper limit of each class.

Q: A study of 4000 Dell PC customers listed the age of the customer among other variables. The youngest customer was 14 years old and the oldest customer was 84 years old. If analysts for the company wish to develop a frequency distribution with 7 classes, the smallest value that the class width can be is 10 years.

Q: There is no difference between cumulative frequency and relative frequency.

Q: One way to develop a frequency distribution using Excel is to use the Frequency function.

Q: In a report describing the number of people in the family of each of the 400 employees at a manufacturing company, the frequency count at the value 3 was 220. This means that the relative frequency at the 3 level is .44.

Q: It is often a good idea to convert frequency distributions to relative frequency distributions when you wish to compare two distributions with different amounts of data.

Q: When developing a frequency distribution, the following classes would be considered acceptable: 5 to < 10 10 to < 20 20 to < 40

Q: Frequency distributions are specifically for analyzing discrete data.

Q: Recently a survey was conducted in which customers of a large insurance company were asked to indicate the number of speeding tickets they had received in the past three years. The minimum value in the data was zero and the largest was six tickets. If you wished to illustrate the proportion of people who had three or fewer tickets, you would most likely construct a cumulative relative frequency distribution.

Q: Recently a survey was conducted in which customers of a large insurance company were asked to indicate the number of speeding tickets they had received in the past three years. The data in this case would most likely be analyzed using a frequency distribution with the data grouped into classes such as 0-2, 3-5, 6-8, etc.

Q: When choosing class boundaries for a frequency distribution, classes such as 60-70, 70-80, 80-90 would be acceptable.

Q: For the same data, a graph of a relative frequency distribution will look exactly the same as a graph of the frequency distribution.

Q: A company has 400 employees. The manager of human resources has recorded the annual salary and wages for each employee. These value range from $17,500 to $67,800. Provide an example of a stem and a leaf that could be developed to describe the distribution of the salary and wage data.

Q: Explain why a relative frequency histogram is sometimes preferable to a regular frequency histogram.

Q: Suppose that you have a data set of 512 observations and the data values range from 36 to 187. What classes would you choose for this data set? Explain why you would choose these values.

Q: Suppose you are given the following data. 99 107 89 94 119 99 87 116 97 101 111 99 93 121 100 115 88 93 83 112 109 116 99 94 109 104 99 96 97 93 103 89 108 94 93 98 If you wish to have a histogram with five classes, what should the first class limits be?

Q: Discuss the steps that you would use to manually construct a histogram for the salaries of the 1,124 employees in the Ferris Steel Company.

Q: Why should a histogram contain no gaps between the bars but a bar chart may have gaps?

Q: Explain why it is appropriate to connect the points on a line graph, but the points on a scatter plot should not be connected.

Q: Explain what information can be conveyed by a frequency histogram.

Q: In creating a frequency distribution for numerical data, describe the steps in choosing the classes.

Q: Assuming you have data for a variable with 2,000 values, using the 2k ≥ n guideline, what is the least number of groups that should be used in developing a grouped data frequency distribution? A) 9 B) 11 C) 13 D) 12

Q: The Fitness Center manager has collected data on the number of visits to the club each week for the past 8 weeks. These data are shown as follows. Which of the following statements is most correct? Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 1415 1623 1934 1879 2102 2156 2511 2499 A) A histogram will illustrate whether a linear relationship exists between the number of visits and the week number. B) A scatter diagram would be useful for displaying these data. C) A line chart for these data will show that an upward trend in the number of visits to the club has occurred over two weeks. D) None of the above

Q: The Fitness Center manager has collected data on the number of visits to the club each week for the past 8 weeks. These data are shown as follows. Which of the following statements is most correct? Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 1415 1623 1934 1879 2102 2156 2511 2499 A) The proper graph for displaying these data is a pie chart. B) There has been a gradual downward trend in these data. C) A frequency histogram should be developed to help identify the trend in these data. D) The data lend themselves to a line chart.

Q: Consider the following chart. Which of the following statements is most correct? A) The values for the dependent variable are determined by the values for the independent variable. B) The values in a scatter plot should be connected by a straight line. C) The variable on the horizontal axis should be the independent variable. D) A scatter plot like this one shows the trend in the data over time.

Q: Consider the following chart. Which of the following statements is most correct? A) There is a negative linear relationship between the two variables. B) There is a positive linear relationship between the two variables. C) There is a perfect linear relationship between the two variables. D) There is no apparent relationship between the two variables.

Q: The sales manager at Western Furniture Company tracked data on the number of customers who came into the store each day and the total dollar volume of sales at the store during the same day. She is considering putting together a report for top management and wishes to show the relationship between these two variables. Which of the following graphs would likely be most useful? She has a sample of 36 days worth of data. A) Scatter diagram B) Bar chart C) Frequency histogram D) Pie chart

Q: Which of the following questions CANNOT be answered using a scatter diagram? A) What is the trend over time of each of the 2 variables? B) Is there a curved or linear relation between the 2 variables? C) Is there a weak or strong relation between the 2 variables? D) Is there a positive or negative relation between the 2 variables?

Q: In constructing a scatter diagram: A) the independent variable should be on the vertical axis. B) the independent variable should be on the horizontal axis. C) the dependent variable should be on the horizontal axis. D) It does not matter which variable goes on which axis.

Q: A scatter diagram can be used to do which of the following? A) Determine the trend in a variable B) Analyze the relationship between two variables C) Describe the basic distribution for a quantitative variable D) Show the percentage of a variable that is associated with each category into which that variable has been divided

Q: The managers at Harris Pizza in Boston have tracked the tips received by their drivers along with the total bill to the customer. An appropriate graph for analyzing the relationship between these two variables is: A) a scatter diagram. B) a line chart. C) a histogram. D) a pie chart.

Q: A line chart is most appropriate for: A) cross-sectional data. B) nominal level data. C) ordinal level data. D) time-series data.

Q: To show how the price of a stock has changed over the last 3 months, the best type of chart to use is: A) a pie chart. B) a histogram. C) a line chart. D) a bar chart.

Q: If two variables show a positive linear relationship in a scatter diagram: A) most of the data values will plot in the lower left-hand quadrant. B) most of the data values will plot in the lower left-hand and upper right-hand quadrants. C) most of the data values will cluster close to the x and y axes. D) the data will cluster in the center of the graph.

Q: One of the advantages that a stem and leaf diagram has over a histogram is: A) the detail of the data is preserved. B) it shows the general distribution of a quantitative variable. C) it can be used with nominal data. D) There are no advantages.

Q: A stem and leaf diagram is an alternative to using: A) a pie chart. B) a bar chart. C) a histogram. D) an ogive.

Q: A stem and leaf diagram is used to: A) display the distribution of a quantitative variable. B) show the joint relationship between two variables. C) graph a joint frequency distribution. D) show relative cumulative frequency.

Q: The Canyon Water Company collects data on the number of gallons of water consumed during a month for each customer. The production manager has divided the usage into 6 classes. To display these data effectively, she could use which of the following types of graphs to convey information about the water usage? A) A stem and leaf diagram B) A bar chart C) A histogram D) Either a histogram or a pie chart

Q: A bar chart possesses which of the following? A) Capability of displaying the distribution for a quantitative variable B) The option of displaying the data in scatter diagram form C) The option for displaying two or more variables on the same chart D) An easy method for displaying the general shape of a continuous variable

Q: The Carter Department Store has data on the sales volume by department for the past 200 days. The data are in an Excel spreadsheet where column A represents the department name and column B represents the sales for each day in that department. In order to construct a bar chart that illustrates the difference in total sales by department for the 200 days, a required step in Excel will be to: A) determine the total sales by department. B) use the frequency function to count the number of occurrences by department. C) group the data into 5 to 20 classes. D) determine the class widths.

Q: Which of the following is true about the difference between stem and leaf diagrams and histograms? A) There is no difference. B) The stem and leaf diagram shows more information by showing the individual values. C) The histogram shows the shape center and spread of the distribution while the stem and leaf does not. D) The stem and leaf diagram shows less information than a histogram.

Q: The Grangeville Power Company has four classifications for its customers. For each customer classification, the company tracks the total amount of electricity used during the year. Which of the following types of graphs would be most appropriate to use? A) A horizontal bar chart B) A vertical bar chart C) Both A and B would be appropriate. D) A histogram

Q: Which of the following is a key difference between a bar chart and a histogram? A) A bar chart typically has gaps between the bars while a histogram has no gaps. B) A bar chart is developed to analyze a continuous variable, while a histogram is used to analyze discrete variables. C) Both A and B are correct. D) There is actually no real difference between a bar chart and a histogram.

Q: A homeowners association consists of 20 homes. The family in each home is considered an automatic member of the association. Recently, one of the homes fell into a state of disrepair. A survey was conducted of the homeowners both on the same street as the house in question and on the second street. At issue was whether legal action should be brought against the homeowner with the problem house. There are 8 homes on the same street as the problem house and 6 of these called for legal action. The percentage of houses on the second street that favored legal action is 50 percent. Which type of chart might be most effective for conveying the information about percentage of residents favoring legal action by street? A) Histogram B) Stem and leaf diagram C) Bar chart D) Pie chart

Q: At a manufacturing plant workers are divided into 4 different teams that rotate shifts. The number of units produced by each team is recorded. The best type of chart to display the data is a: A) pie chart. B) histogram. C) ogive. D) line chart.

Q: Which of the following is a false statement? A) A bar chart is usually constructed so that gaps exist between the bars. B) The bars on a bar chart can be different colors. C) A histogram is usually constructed without gaps between the bars. D) A bar chart and histogram can typically be used interchangeably.

Q: The city counsel has just voted to pass the city's budget for next year. If you were writing a report describing the budget so the citizens could understand how the total tax dollars will be spent, which of the following graphs might be most appropriate? A) Pie chart B) Scatter diagram C) Histogram D) Ogive

Q: One of the key differences between a bar chart and histogram is: A) the histogram contains gaps between the bars and the bar chart does not. B) a bar chart is used to display a categorical variable and a histogram is used to display the distribution of a quantitative variable. C) the histogram shows relative frequency while the bar chart shows frequency. D) the bar chart must be vertical while the histogram must be horizontal.

Q: A study was recently conducted by the regional electric and gas company. Data were collected for three customer categories showing the dollar amount of natural gas and the dollar amount of electricity consumed during the year. Which of the following graphs would most likely be used to display both sets of data together? A) Pie chart B) Bar chart C) Line chart D) Histogram

Q: A bar chart is most likely used to display which of the following? A) A continuous variable B) A nominal level variable C) An ordinal level variable D) Either B or C

Q: One characteristic of a bar chart is: A) the bars can be displayed either vertically or horizontally. B) there can be no gaps between the bars. C) it is used to display the distribution of a continuous variable. D) it shows cumulative frequency.

Q: Which of the following is NOT true of a bar chart? A) It is used for numerical data. B) The bars can be either horizontal or vertical. C) It can show either frequency or relative frequency. D) It is used for categorical data.

Q: Which of the following CANNOT be shown effectively with a histogram? A) A frequency distribution B) A joint frequency distribution C) A relative frequency distribution D) The center, shape and spread of a distribution

Q: The undergraduate students at your university are classified as freshmen, sophomores, juniors, or seniors. A recent study of undergraduates asked the students to indicate the number of credits they were registered for this term. The responses were 3, 6, 9, 12, 15, and 18. The number of cells in a joint frequency distribution for the two variables, class standing, and credit hours is: A) 4. B) 10. C) 24. D) None of the above.

Q: A study was recently done in which the brand preference for breakfast cereal was analyzed against the gender of the shopper. The study consisted of 200 male shoppers and 300 female shoppers. Three different cereal brands were considered: A, B, and C. A total of 250 female shoppers preferred brand A, 25 female shoppers preferred brand C. A total of 100 shoppers preferred brand B. The number of male shoppers that preferred brand B was: A) 25. B) 100. C) 75. D) 50.

Q: A study was recently done in which the brand preference for breakfast cereal was analyzed against the gender of the shopper. The study consisted of 200 male shoppers and 300 female shoppers. Three different cereal brands were considered: A, B, and C. A total of 250 female shoppers preferred brand A, 25 female shoppers preferred brand C. The number of female shoppers that preferred brand B was: A) 25. B) 100. C) 75. D) 50.

Q: Joint frequency distributions are used to display: A) the histograms of two variables analyzed simultaneously. B) the number of occurrences at each of the possible joint occurrences of two variables. C) the cumulative distribution of a variable with two possible outcomes. D) the relative frequency of two variables.

Q: Which of the following is a reason for constructing a joint frequency distribution? A) To determine the trend between the two variables B) To measure the spread between the two variables C) To help analyze the relationship between the two variables D) To show the average of two variables

Q: A frequency histogram should be computed from which type of data? A) Quantitative data B) Categorical data C) Nominal level data D) Ordinal data

Q: In forming the classes for a frequency distribution and histogram, suppose there were a number of empty classes. You should: A) increase the class width. B) decrease the class width. C) keep the current class width. D) use an ogive instead.

Q: When using Excel's Histogram option under the Data Analysis tool, the term bins refers to: A) the mid-point of each class. B) the column where the data are located. C) the upper limits of each class. D) the lower limits of each class.

Q: A histogram is used to display which of the following characteristics for a quantitative variable? A) The approximate center of the data B) The spread in the data C) The shape of the distribution D) All of the above.

Q: Many Walmart stores have automotive departments where customers can buy tires, have their vehicles serviced, and obtain other automotive services. Recently, the manager at an Ohio Walmart collected data on the time customers had to wait to get the desired automotive service. Of the 500 cars in the sample, the shortest time any customer spent waiting was 3 minutes and the longest time was 183 minutes. Assuming that the manager wishes to develop a frequency distribution with 9 classes, which of the following would be an appropriate class width for each class? A) 10.50 B) 19.99 C) 20.00 D) 3 to 23

Q: Explain the difference between a stratified random sample and cluster random sample.

Q: As a member of the student council at your university, you have been assigned the task of conducting a phone survey of undergraduate students to determine satisfaction with the campus food service. Explain how you would go about selecting a simple random sample.

Q: In a survey, what is meant by demographic questions and why might we want to include demographic questions in survey?

Q: What are the major categories of statistical tools that will be covered in this course?

Q: Of the following techniques for collecting data, which one is generally considered the least costly to implement: experiments, telephone surveys, mail questionnaires, direct observation, personal interview?

Q: Open the data file provided with the text called Computer Use. Indicate the level of data measurement for each variable in the data set.

Q: Open the data file provided with the text called AirlinePassengers. Indicate the level of data measurement for each variable in the data set.

Q: Explain the difference between stratified random sampling and cluster random sampling.

Q: What is the underlying common element of all statistical sampling techniques?

Q: Is there ever a reason why we might prefer to work with a sample rather than with an entire population? Discuss.

Q: Discuss the two major types of descriptive statistics.