Statistics Data Analysis and Decision Modeling Descriptive Statistics.docx

Statistics, Data Analysis, and Decision Modeling Descriptive Statistics and Data Analysis 1) ________ refers to a collection of quantitative measures and ways of describing data. A) Statistical inference B) Descriptive statistics C) Frequency distribution D) Categorical data Answer: B 2) All of the following are examples of measures of central tendency except ________. A) mean B) median C) standard deviation D) mode Answer: C 3) All of the following are examples of measures of dispersion except ________. A) range B) variance C) standard deviation D) mode Answer: D 4) In Microsoft Excel 2010, the function that computes the standard deviation of a set of data, assumed to be a sample, is ________. A) STDEV.P(data range) B) MODE.SNGL(data range) C) STAND.MULT(data range) D) STDEV.S(data range) Answer: D 5) In Microsoft Excel 2010, the function that computes the standard deviation of a set of data, assumed to be a population, is ________. A) STDEV.S(data range) B) STAND.SNGL(data range) C) STDEV.P(data range) D) STAND.MULT(data range) Answer: C 6) In Microsoft Excel 2010, the function that computes the single most frequently occurring value in a set of data is ________. A) MEDIAN(data range) B) MODE.SNGL(data range) C) STDEV.P(data range) D) SKEW(data range) Answer: B 7) Using Microsoft Excel 2010, the function that computes the most frequently occurring values of a set of data is ________. A) MODE.SNGL(data range) B) MEDIAN(data range) C) STDEV.P(data range) D) MODE.MULT(data range) Answer: D 8) A table that shows the number of observations in each of several nonoverlapping groups is called a ________. A) frequency distribution B) scatter plot C) histogram D) chart Answer: A 9) The sum of relative frequencies will always equal ________. A) 100 B) 1.0 C) 10 D) 0.01 Answer: B 10) A graphical depiction of a frequency distribution for numerical data in the form of a column chart is called a ________. A) scatter plot B) box-and-whisker plot C) pie chart D) histogram Answer: D 11) The proportion of the total sample that falls at or below the upper limit value is represented by ________. A) dispersion B) cumulative relative frequency C) median D) standard deviation Answer: B 12) The ________ is a value at or below which at least k percent of the observations lie. A) kth percentile B) kth ratio C) kth quartile D) kth mean Answer: A 13) The formula to calculate kth percentile is given by ________. A) 100/Nk + 0.05 B) 100/Nk - 0.05 C) Nk/100 + 0.05 D) Nk/100 - 0.05 Answer: C 14) ________ is the quartile representing the 25th percentile. A) Q1 B) Q2 C) Q3 D) Q4 Answer: A 15) ________ is the quartile representing the 50th percentile. A) Q1 B) Q2 C) Q3 D) Q4 Answer: B 16) ________ is the quartile representing the 75th percentile. A) Q1 B) Q2 C) Q3 D) Q4 Answer: C 17) ________ is the quartile representing the 100th percentile. A) Q1 B) Q2 C) Q3 D) Q4 Answer: D 18) One-fourth of the data falls below the ________ quartile. A) fourth B) second C) first D) third Answer: C 19) Three-fourths of the data fall below the ________ quartile. A) fourth B) second C) first D) third Answer: D 20) The ________ is the sum of all observations divided by the number of observations. A) arithmetic mean B) median C) mode D) midrange Answer: A 21) The ________ is the middle value when the data are arranged from smallest to largest. A) mode B) median C) midrange D) arithmetic mean Answer: B 22) The ________ is the observation that occurs the most frequently in the data set. A) arithmetic mean B) median C) mode D) midrange Answer: C 23) The ________ is the average of the largest and smallest values in the data set. A) arithmetic mean B) median C) mode D) midrange Answer: D 24) An observation that is radically different from the rest is called ________. A) the median B) the mean C) an outlier D) the mode Answer: C 25) The population mean is represented by ________. A) ? B) ? C) ? D) ? Answer: B 26) The sample mean is represented by ________. A) B) ? C) ? D) ? Answer: A 27) The midrange for a data set containing all the values between 50 and 67 is ________. A) 67 B) 58.5 C) 50 D) -17 Answer: B 28) The degree of variation in or the numerical spread of the data is known as ________. A) quartile B) median C) dispersion D) mean Answer: C 29) Which of the following can be used to represent dispersion in a data set? A) proportion B) range C) mode D) median Answer: B 30) Which of the following provides an estimate that represents "centering" of the entire set of data? A) range B) variance C) midrange D) standard deviation Answer: C 31) Computing the difference between the maximum value and the minimum value gives the ________ of the data set. A) variance B) standard deviation C) range D) median Answer: C 32) The range of the middle 50% of the data is called the ________. A) midrange B) interquartile range C) variance D) mode Answer: B 33) The sample variance is denoted as ________. A) s2 B) v2 C) ?2 D) ?2 Answer: A 34) The population variance is denoted as ________. A) s2 B) v2 C) ?2 D) ?2 Answer: C 35) The square root of the variance is called the ________. A) mean B) standard deviation C) median D) interquartile range Answer: B 36) The standard deviation for the population is denoted as ________. A) ? B) ? C) s D) ? Answer: D 37) The standard deviation for a sample is denoted as ________. A) ? B) ? C) s D) ? Answer: C 38) Which of the following state(s) that for any set of data, the proportion of values that lie within k standard deviations (k>1) of the mean is at least 1 - 1/k2? A) empirical rules B) interquartile range C) Chebyshev's theorem D) standard deviation Answer: C 39) Using Chebyshev's theorem, k = 2 would mean that ________. A) at least two-thirds of the data lie within two standard deviations of the mean B) at least 89% of the data lie within two standard deviations of the mean C) less than three-fourths of the data lie within three standard deviations of the mean D) at least three-fourths of the data lie within two standard deviations of the mean Answer: D 40) Using Chebyshev's theorem, k = 3 means that ________. A) at least two-thirds of the data lie within three standard deviations of the mean B) at least 89% of the data lie within three standard deviations of the mean C) less than 29% of the data lie within three standard deviations of the mean D) at least three-fourths of the data lie within two standard deviations of the mean Answer: B 41) Which of the following is included in the empirical rules? A) Approximately 59% of the observations will fall within two standard deviations of the mean, or within x ± 2s. B) Approximately 68% of the observations will fall within one standard deviation of the mean, or between x - s and x + s. C) Approximately 89% of the observations will fall within three standard deviations of the mean, or within x ± 3s. D) Approximately 28% of the observations will fall within three standard deviations of the mean, or within x ± 3s. Answer: B 42) According to the empirical rules, approximately 99.7% of the observations will fall within ________. A) one standard deviation of the mean B) two standard deviations of the mean C) three standard deviations of the mean D) four standard deviations of the mean Answer: C 43) According to the empirical rules, approximately 95% of the observations will fall within ________. A) one standard deviation of the mean B) two standard deviations of the mean C) three standard deviations of the mean D) four standard deviations of the mean Answer: B 44) The ________ is used to compare the variability of two or more data sets with different scales. A) coefficient of variation B) variance C) median D) coefficient of skewness Answer: A 45) The coefficient of variation (CV) is calculated as ________. A) mode/standard deviation B) standard deviation/mean C) standard deviation/variance D) range/standard deviation Answer: B 46) Given that the standard deviation is equal to 0.568, the median equals 5, and the mean value is 3.5, what is the value of the coefficient of variation? A) 0.1136 B) 0.162 C) 6.16 D) 0.7 Answer: B 47) When more of the mass of the data is concentrated on one side and the distribution of values tails off to the other side, the histogram is said to be ________. A) symmetric B) skewed C) curved D) positively sloped Answer: B 48) When a histogram is positively skewed, it ________. A) tails off to the right B) is symmetrical C) tails off to the left D) has a slope greater than one Answer: A 49) When a histogram is negatively skewed, it ________. A) is symmetrical B) tails off to the left C) has a slope lesser than one D) tails off to the right Answer: B 50) The degree of asymmetry of observations around the mean is measured by the ________. A) coefficient of correlation B) coefficient of symmetry C) coefficient of skewness D) coefficient of deviation Answer: C 51) Which of the following coefficients of skewness values has the lowest degree of skewness? A) 1 B) 1.1 C) 0.5 D) 0.05 Answer: D 52) A coefficient of skewness that indicates relative symmetry would lie between ________. A) 0.5 and -0.5 B) 5 and -5 C) 1 and -1 D) 0.95 and 1 Answer: A 53) A coefficient of skewness that indicates moderate skewness would lie between ________. A) 1 and 2 B) 0.5 and 1 C) 0 and 1 D) 0.5 and -0.5 Answer: B 54) A histogram with only one peak ________. A) does not have a mode value B) is unimodal C) is bimodal D) has a high degree of kurtosis Answer: B 55) A histogram with exactly two peaks ________. A) is unimodal B) has a low degree of kurtosis C) has the same values for mean and mode D) is bimodal Answer: D 56) If the distribution of observations were perfectly symmetrical and unimodal, ________. A) the mean would be greater than the mode B) the mean, median, and mode would be the same C) the mode would be lesser than the median D) the median would be greater than the mean Answer: B 57) The degree of flatness or peakedness of a population is measured by the ________. A) coefficient of kurtosis B) coefficient of skewness C) coefficient of variation D) coefficient of deviation Answer: A 58) A distribution that is relatively flat with a wide degree of dispersion has a coefficient of kurtosis that is ________. A) more than 3 B) less than 3 C) less than 6 D) more than 6 Answer: B 59) A distribution that is relatively peaked with a low degree of dispersion has a coefficient of kurtosis that is ________. A) equal to 0 B) less than 0 C) more than 3 D) equal to 3 Answer: C 60) ________ is a measure of a linear relationship between two variables. A) Variance B) Proportion C) Correlation D) Kurtosis Answer: C 61) The correlation coefficient is a number between ________. A) 0 and +1 B) -1 and 0 C) -1 and +1 D) -2 and +2 Answer: A 62) The correlation coefficient for two variables that are not linearly related will be equal to ________. A) 1 B) 2 C) 0 D) 3 Answer: C 63) What does a positive correlation coefficient indicate? A) When one variable increases, the other variable decreases. B) When one variable increases, the other variable also increases. C) When one variable decreases, the other variable remains constant. D) Both the variables are not linearly related. Answer: B 64) What does a negative correlation coefficient indicate? A) When one variable increases, the other variable decreases. B) There is a nonlinear relationship between the two variables. C) When one variable increases, the other variable increases by a smaller proportion. D) A change in one variable does not lead to a change in the other variable. Answer: A 65) The formal statistical measure for categorical data is called the ________. A) sample mean B) sample median C) sample mode D) sample proportion Answer: D 66) Sample proportion is usually denoted as ________. A) sp B) p C) p2 D) s Answer: B 67) The subcategories of the variables in a contingency table must ________. A) be mutually exclusive B) sum up to a total of 1 C) be arranged in ascending order D) lie between 0 and 1 Answer: A for Categorical Data 68) A ________ displays the minimum, first quartile, median, third quartile, and maximum of a data set. A) scatter plot B) contingency table C) box plot D) stacked column chart Answer: C Topic: Visual Display of Statistical Measures 69) In a box-and-whisker plot, the whiskers represent the ________. A) Q1 and Q3 B) minimum and maximum values C) median and mode D) cumulative frequencies Answer: B Topic: Visual Display of Statistical Measures 70) In a box plot, the outer boundaries of the box represent the ________. A) interquartile range B) median and mode C) minimum and maximum D) outlier values Answer: A Topic: Visual Display of Statistical Measures 71) In a box plot, the line inside the box represents the ________. A) mean B) median C) mode D) range Answer: B Topic: Visual Display of Statistical Measures 72) Outliers defined as being between 1.5*IQR and 3*IQR to the left of Q1 or to the right of Q3 are considered ________. A) weak B) extreme C) mild D) statistically significant Answer: C Topic: Visual Display of Statistical Measures 73) Outliers defined as being more than 3*IQR away from Q1 and Q3 are considered ________. A) mild B) extreme C) weak D) irrelevant Answer: B Topic: Visual Display of Statistical Measures 74) Which of the following is true of outliers in a data set? A) All outliers should be eliminated in order to portray accurate information. B) Outliers that are within 1 standard deviation of the mean must be eliminated. C) The mean and range are sensitive to outliers in the data. D) Outliers do not make any difference in the results obtained from statistical analyses. Answer: C Topic: Visual Display of Statistical Measures 75) Pivot tables can be used to create ________. A) dot-scale diagrams. B) box-and-whisker plots. C) cross-tabulations for categorical data. D) scatter plots. Answer: C Topic: Data Analysis Using Pivot tables 76) Frequency distributions can only be constructed for numerical data. Answer: FALSE 77) The sum of relative frequencies must equal 100. Answer: FALSE 78) The cumulative relative frequency represents the proportion of the total sample that falls at or below the upper limit value. Answer: TRUE 79) Point estimates that accurately represent population parameters are called outliers. Answer: FALSE 80) The standard deviation is the square root of the variance. Answer: TRUE 81) The formula used for calculating the variance of a population is different from that used for calculating the variance of a sample. Answer: TRUE 82) A negative correlation coefficient indicates a linear relationship between variables where one variable increases as the other increases. Answer: FALSE 83) Statistics such as means and variances are not appropriate for categorical data. Answer: TRUE 84) Box-and-whisker plots graphically display five key statistics of a data set: the minimum, first quartile, mean, third quartile, and maximum. Answer: FALSE 85) Box plots and dot-scale diagrams can help identify possible outliers visually. Answer: TRUE 86) For a stock that displays a large standard deviation, the returns may be high but risk is high too. Answer: TRUE 87) According to the empirical rules, approximately 38% of the observations will fall within two standard deviations of the mean. Answer: FALSE 88) The coefficient of variation (CV) provides a relative measure of the dispersion in data relative to the mean. Answer: TRUE 89) For a negatively skewed distribution, the mode is greater than the median, which is greater than the mean. Answer: TRUE 90) The higher the kurtosis, the more area the histogram has in the middle rather than in the tails. Answer: FALSE 91) Sketch a positively skewed distribution. Answer: 92) Sketch a negatively skewed distribution. Answer: 93) Sketch a perfectly symmetrical and unimodal distribution. Answer: 94) Sketch a bimodal distribution. Answer: Use the table below to answer the following question(s). The table shows the crude oil prices in dollars per barrel, for 2007. Jan: $54.63 Feb: $52.11 Mar: $57.83 Apr: $64.93 May: $63.40 Jun: $65.37 Jul: $69.91 Aug: $73.81 Sep: $71.42 Oct: $75.57 Nov: $86.02 Dec: $85.91 95) Calculate the mean price of crude oil in 2007. Answer: $68.41 96) Locate the median price of crude oil in 2007. Answer: $67.64 97) Sketch a normal distribution and label the sections of the empirical rules. Answer: According to the empirical rules: 1. Approximately 68% of the observations will fall within one standard deviation of the mean. 2. Approximately 95% of the observations will fall within two standard deviations of the mean. 3. Approximately 99.7% of the observations will fall within three standard deviations of the mean. 98) Explain Chebyshev's theorem. Answer: Chebyshev's theorem states that for any set of data, the proportion of values that lie within k standard deviations (k >1) of the mean is at least 1 - 1/k2. Thus, for k = 2 at least three-fourths of the data lie within two standard deviations of the mean; for k = 3 at least , or 89%, of the data lie within three standard deviations of the mean. 99) List three statistical measures that characterize dispersion. Answer: Range is the difference between the maximum and minimum values in a data set and measures how spread out the data is. Variance involves all the values in the data set and measures how spread out the data is around the mean. The third measure is the standard deviation, which is defined as the square root of the variance.