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The Practice of Statistics – Chapter 1 Reading 1.1A: Pages 2 – 6 Statement T or F 1. Statistics is the science of data. T F 2. Individuals are the “What” of the data. T F 3. A variable is a characteristic of an individual T F 4. All numbers are classified as quantitative data. T F 5. The type of data determines how to analysis and graph the information T F 6. A variable generally takes values that vary. T F 7. A distribution is the way something is divided up or spread out. T F 8. When exploring data, first look at the numeric summaries (mean, standard deviation, median, etc.) T F 9. Inference is the process of reaching a conclusion for a population based on the data from a sample. T F 1.1B: If False, make a correct statement Pages 7 – 11 Statement T or F 10. The distribution of a categorical variable list the categories and gives the count of individuals who fall within each category. T F 11. A pie chart or histogram display the distribution of a categorical variable more vividly. T F 12. A pie chart must include all the categories that make up a whole. T F 13. Pie charts are used to emphasize each category’s relation to the whole. T F 14. In a bar graph, the bar heights show the category counts or percents. T F 15. When drawing a bar graph, make the bars equally wide. T F 16. To increase eye appeal on a bar graph, replace bars with pictures. T F If False, make a correct statement 1.1C: Pages 11 – 19 Statement T or F 17. When analyzing a two-way table, begin by looking at the distribution of each variable separately. T F 18. On a two-way table, if the row and column total are missing, these totals should be calculated first. T F 19. The marginal distribution of one of the categorical variables in a two-way table of counts is the distribution of values of that variable among all individual described by the table. T F 20. Counts are often more informative than percents. T F 21. Marginal distributions tell us about the relationship between two variables. T F T F T F T F T F T F 22. A conditional distribution of a variable describes the values of that variable among individuals who have a specific value of another variable. 23. A segmented bar graph is used to compare the distribution of a categorical variable in each of several groups. 24. An association between two variables is when knowing the value of one variable will not help predict the value of the second. 25. If there is no association between two variables, then the segmented bar graph for the two variables would look the same. 26. If two variables are strongly associated, they may be influenced by a segmented variable. 1.2A: If False, make a correct statement Pages 25 – 33 Statement T or F 27. One of the simplest graphs to construct is a line graph. T F 28. The purpose of making a graph is to help understand the data, T F 29. In any graph, look for the overall pattern and for striking departures from that pattern. T F 30. You can describe the overall pattern of a distribution by it shape and center. T F 31. An outlier is an individual value that falls outside the overall pattern. T F 32. When you describe the shape of the distribution, concentrate on all the ups and downs. T F 33. When you describe the shape of the distribution, look for clusters of values, obvious gaps, and potential outliers. T F If False, make a correct statement 34. A skewed distribution is when one side of the graph is much longer than the other. T F 35. The direction of the skewness is the direction of where most of the data are clustered and not in the direction of the long tail. T F 36. A unimodal distribution have a single clear peak whereas a bimodal has two clear peaks. T F 37. A stemplot gives us a quick picture of the shape of a distribution while including the actual numerical values in the graph. T F 38. Stem plots work well with large data sets. T F 39. When creating a stemplot, it is a good idea to round numbers so that the final digit after rounding is suitable as a leaf. T F 40. One of the simplest graphs to construct is a line graph. T F 41. The purpose of making a graph is to help understand the data, T F 42. In any graph, look for the overall pattern and for striking departures from that pattern. T F 43. You can describe the overall pattern of a distribution by it shape and center. T F 44. An outlier is an individual value that falls outside the overall pattern. T F 45. When you describe the shape of the distribution, concentrate on all the ups and downs. T F 46. When you describe the shape of the distribution, look for clusters of values, obvious gaps, and potential outliers. T F 47. A skewed distribution is when one side of the graph is much longer than the other. T F 48. The direction of the skewness is the direction of where most of the data are clustered and not in the direction of the long tail. T F 49. A unimodal distribution have a single clear peak whereas a bimodal has two clear peaks. T F 50. A stemplot gives us a quick picture of the shape of a distribution while including the actual numerical values in the graph. T F 51. Stem plots work well with large data sets. T F 52. When creating a stemplot, it is a good idea to round numbers so that the final digit after rounding is suitable as a leaf. T F 1.2B: Pages 33– 40 Statement T or F 53. In making a histogram, first divide the data into classes of equal width. T F 54. In making a histogram, second find how many of the individuals belong in each class. T F 55. In making a histogram, third label and scale your axes and draw the histogram. T F 56. In a histogram, eight classes is a good minimum. T F 57. A histogram is the same thing as a bar graph. T F 58. When comparing distributions with different numbers of observations, it is a good practice to use percents instead of counts. T F 59. When a graph looks nice, the data will have meaning. T F 1.3A: If False, make a correct statement Pages 48 – 59 Statement T or F 60. The most common measure of center is the mean. T F 61. When symbol, 𝑥̅ , is the symbol used for the mean of a population. T F 62. The mean is sensitive to the influence of extreme observations. T F 63. The median is the balancing point of the distribution. T F 64. In a symmetrical distribution the mean and median are close to equal. T F 65. When a distribution is skewed, use the mean to describe the center. T F 66. A useful numerical description require3s both a measure of center and a measure of spread. T F 67. The range of a distribution is the largest value minus the smallest value. T F 68. IQR = Q1 – Q3 T F 69. The quartiles and interquartile range is resistant because they are not affected by a few extreme values. T F 70. An outlier is any value that falls more than 1.5 x IQR above the third quartile or below the first quartile. T F If False, make a correct statement 71. The five-number summary consists of Min, Q1, Mean, Q3, and Max. T F 72. Use the five-number summary to construct a box plot. T F 73. Boxplots are best used to show side-by-side comparison of more than one distribution. T F 1.3B: Pages 60 – 67 Statement T or F 74. The standard deviation and variance measure spread by looking at how far the observations are from their mean. T F 75. 𝑠𝑥 is the symbol used for the standard deviation of a sample. T F 76. The standard deviation is 0 when all values in a data set are equal. T F 77. The standard deviation is measured in the same units as the original observation. T F 78. If a distribution is symmetrical, use the mean for the center and the IQR for the spread. T F 79. All summaries should include a plot of the data. T F If False, make a correct statement The Practice of Statistics – Chapter 2 Reading 2.1A: Pages 85 – 91 Statement T or F 1. The 70th percentile of a distribution is the value with 70% of the observation less than it. T F 2. To make a cumulative relative frequency graph, we plot a point corresponding to the cumulative relative frequency in each class at the smallest value of the next class. T F 3. The first quartile is equal to the 25th percentile. T F 4. We describe the location of a value in a distribution by how many standard deviation it is away from the median. To standardize a value, subtract the mean of the distribution and then divide the difference by the standard deviation. T F T F 5. 6. A z-score tells us how many standard deviation from the mean an observation falls and in what direction. T F 7. We often standardize observations only if they are on the same scale. T F 2.1B: If False, make a correct statement Pages 92 – 97 Statement T or F 8. Transforming data converts the observation form the original units of measurement to a standardized scale. T F 9. Adding a number to each value in a distribution will not change the mean. T F 10. Adding a number to each value in a distribution will not change the standard deviation. T F 11. Adding a number to each value in a distribution will not change the shape. T F 12. Multiplying a number to each value in a distribution will not change the mean. T F 13. Multiplying a number to each value in a distribution will not change the standard deviation. T F 14. Multiplying a number to each value in a distribution will not change the shape. T F If False, make a correct statement 2.2A: Pages 104 – 117 Statement T or F 15. A density curve is a curve has an area of exactly 1 underneath it. T F 16. A density curve can describe exactly the real data. T F 17. The median of a density curve is the point that divides the area under the curve in half.. T F 18. The mean of a density curve is the point at which the curve would balance if made of solid material. T F 19. The median of a skewed curve is pulled away from the mean in the direction of the long tail. T F 20. All Normal curves have the same overall shape: symmetric, unimodal and bell-shaped. T F 21. A Normal curve can be described completely by its median and standard deviation. T F 22. The points at which the change in curvature takes place are located at a distance of one standard deviation on either side of the mean. T F 23. N(10, 2) describes a Normal distribution with a standard deviation of 10 and a mean of 2. T F 24. Normal distributions are good descriptions for some distributions of real data. T F 25. Many statistical inference procedures are based on Normal distributions. T F 26. In a Normal distribution approximately 68% of the observation fall within two standard deviation. T F 27. The 58-95-99.7 rule is sometimes called the Imperial Rule T F 28. All models are wrong, and all are useful. T F 29. N(0, 1) is the standard Normal distribution. T F 30. Any question about what proportion of observations lies in some range of values can be answered by finding an area under the curve. T F 31. Always sketch the standard Normal curve, mark the zvalue and shade the area of interest. T F 32. To find area under the Normal distribution, you must use the table in the back of the book. T F If False, make a correct statement 2.2B: Pages 118 – 120 Statement T or F 33. You should always answer the question with a complete sentence. T F 34. Using technology, you can find values from a given area. T F 2.2C: If False, make a correct statement Pages 121 – 125 Statement 35. A Normality probability plot provides a good assessment of whether a data set follows a Normal distribution. 36. Even a small wiggle in a Normal probability plot is enough information to determine a distribution is not Normal. 37. If the points on a Normal probability plot lie close to a straight line, the data are approximately Normally distributed. T or F T F T F T F If False, make a correct statement The Practice of Statistics – Chapter 3 Reading 3.1A: Pages 142 – 149 Statement T or F 1. A response variable measures an outcome of a study. T F 2. An explanatory variable may help explain or predict changes in a response variable. T F 3. A scatterplot show the relationship between two quantitative variables measured on different individuals. T F 4. Always plot the response variable on the horizontal axis of a scatterplot. T F 5. You can describe the overall pattern of a scatterplot by the direction, form and strength. T F 6. An important kind of departure is an outlier, a value that falls outside the overall pattern of the relationship. Two variables have a negative association when above-average values of one tend to accompany above-average values of the other. T F T F 7. 3.1B: If False, make a correct statement Pages 150 – 157 Statement T or F 8. Our eyes are good judges of how strong a linear relationship is. T F 9. The correlation measures the direction and strength of the linear relationship between two quantitative variables. T F 10. The letter “c” is used as the symbol representing correlation. T F 11. Correlation is always a number between 0 and 1 T F 12. A correlation value of 0 indicate a very weak linear relationship. T F 13. Use a calculator to find the correlation coefficient. T F 14. Correlation makes a distinction between explanatory and response variable. If you switch the two variables you will get a different correlation. T F 15. The correlation does not change when we change the units of measure of x, y, or both T F 16. The correlation is measured in the units of the explanatory variable. T F If False, make a correct statement 17. Correlation does not imply causation. T F 18. Correlation works for both quantitative and categorical variable. T F 19. Correlation only explains the linear relationship between two variables. T F 20. A value of r close to 1 or -1 guarantee a linear relationship between two variable. T F 21. The correlation is strongly affected by an outlier T F 22. Correlation is a complete summary of two-variable data. T F 3.2A: Pages 164 – 168 Statement T or F 23. A regression line is a line that describes how a response variable x changes as an explanatory variable y changes. T F 24. A regression line is a model to describe a relationship. T F 25. 𝑦̂ is the symbol use for the predicted value T F 26. The slope is the amount by which x is predicted to change when y increases by one unit. T F 27. The y-intercept is the predicted value of y when x = 0. T F 28. The y– intercept is meaningful for all explanatory variables. T F 29. You can determine how strong a relationship is by looking at the size of the slope of the regression line. T F 30. Extrapolation is the use of a regression line for prediction far outside the interval of values of the explanatory variable x used to obtain the line T F 31. Extrapolated values of often accurate. T F 3.2B: If False, make a correct statement Pages 168 – 176 Statement T or F 32. A good regression line makes the horizontal deviation of the points from the line as small as possible. T F 33. A residual is the vertical difference between an observed value of the response variable and the value predicted by the regression line. T F If False, make a correct statement 34. T F 35. T F 36. T F 37. T F 38. T F 39. T F 40. T F 41. T F 42. T F 43. T F 44. T F 45. T F 46. T F 47. T F 48. T F 49. T F 3.2C: Pages 177 – 180 Statement T or F 50. T F 51. T F 52. T F If False, make a correct statement 53. T F 54. T F 55. T F 56. T F 57. T F 58. T F 59. T F 60. T F 61. T F 62. T F 63. T F 64. T F 65. T F 66. T F 67. T F 3.2D: Pages 181 – 191 Statement T or F 68. T F 69. T F 70. T F 71. T F If False, make a correct statement 72. T F 73. T F 74. T F 75. T F 76. T F 77. T F 78. T F 79. T F 80. T F 81. T F 82. T F 83. T F 84. T F 85. T F