Business Analytics Exam 2

Compute the third quartile for the following data. 10, 15, 17, 21, 25, 12, 16, 11, 13, 22 a. 21.25 b. 11.75 c. 15.5 d. 21.5

a. 21.25 Quartiles divide data into four parts, with each part containing approximately one-fourth, or 25 percent, of the observations. This can be calculated with the Excel function =QUARTILE.EXC(range,3) = 21.25.

Compute the mean of the following data. 56, 42, 37, 29, 45, 51, 30, 25, 34, 57 a. 40.6 b. 39.4 c. 42.8 d. 52.1

a. 40.6 The mean provides a measure of central location. ​

Skewed right vs skewed left?

Skewed right falls right (higher on left to lower on right) Skewed left falls left (higher on right to lower on left)

What is the total relative frequency? ​ a. 99.12 b. Not enough information c. 1 d. 0.88

c. 1 The relative frequencies always add to 1

The charts that are helpful in making comparisons between categorical variables are a. column charts and line charts. b. bar charts and scatter charts. c. bar charts and column charts. d. scatter charts and line charts.

c. bar charts and column charts. Bar charts and column charts provide a graphical summary of categorical data, and they are very helpful in making comparisons between categorical variables.

Consider the clustered bar chart of the dashboard developed to monitor the performance of a call center: Chart shows location v number of calls (bar chart w/ email, internet, software options) This chart allows the IT manager to a. identify how often a problem is related to hardware. b. identify which city contains the most customers. c. identify the frequency of a particular type of problem by location. d. identify the percent of customers who do not have one of the listed problems.

c. identify the frequency of a particular type of problem by location. The clustered bar chart shows the call volume in the call center by type of problem (Email, Internet, or Software) for each of three cities in Texas. This chart allows the IT manager to quickly identify if there is a particular type of problem by location.

Tables should be used instead of charts when a. the reader need not differentiate the columns and rows. b. the reader needs relative comparisons of data. c. the values being displayed have different units or very different magnitudes. d. there are more than two columns of data.

c. the values being displayed have different units or very different magnitudes. Tables should be used when the reader needs to refer to specific numerical values, when the reader needs to make precise comparisons between different values and not just relative comparisons, and when the values being displayed have different units or very different magnitudes.

Data collected from several entities over a period of time (minutes, hours, days, etc.) are called a. categorical and quantitative data. b. cross-sectional data. c. time series data. d. source data.

c. time series data. Data that are collected over a period of time (minutes, hours, days, months, years, etc.) are known as time series data.

The distribution of hourly sales for a local family owned store is normally distributed with a mean of $225 per hour and a standard deviation of $75 per hour. Which of the following intervals contains the middle 95% of hourly sales? a. $150 to $300 b. $175 to $275 c. $125 to $325 d. $75 to $375

d. $75 to $375 In a normal curve, approximately 95% of observations fall within 2 standard deviations of the mean.

Compute the coefficient of variation for the following sample data. 32, 41, 36, 24, 29, 30, 40, 22, 25, 37 a. 18.64% b. 21.67% c. 20.28% d. 21.36%

d. 21.36% The coefficient of variation indicates how large the standard deviation is relative to the mean. The coefficient of variation is (6.75 / 31.6 × 100) = 21.36%.

A sample of 13 adult males' heights are listed below. Find the range of the data.​ 70, 72, 71, 70, 69, 73, 69, 68, 70, 71, 67, 71, 74 a. 4 b. 5 c. 6.5 d. 7

d. 7 The simplest measure of variability is the range. The range can be found by subtracting the smallest value from the largest value in a data set. Range = 74 - 67 = 7.

The amount of time taken by each of 10 students in a class to complete an exam is an example of what type of data? a. Cannot be determined b. Categorical data c. Time series data d. Quantitative data

d. Quantitative data Data are considered quantitative data if numeric and arithmetic operations, such as addition, subtraction, multiplication, and division, can be performed on them.

Which of the following relationships would have a negative correlation coefficient? a. The square footage of a home and the price of the home b. Cost of a car and the amount of tax to be paid c. Amount of a bill at a restaurant and the amount of the tip d. Supply and demand

d. Supply and demand A relationship will have a negative correlation coefficient if as one variable increases the other variable decreases.

The correlation coefficient will always take values a. less than -1. b. between -1 and 0. c. greater than 0. d. between -1 and +1.

d. between -1 and +1. The correlation coefficient will always take values between -1 and +1.

An alternative for a stacked column chart when comparing more than a couple of quantitative variables in each category is a a. stacked bar chart. b. pie chart. c. clustered bar chart. d. clustered column chart.

d. clustered column chart. Experts often recommend against the use of stacked column bar charts for more than a couple of quantitative variables in each category. An alternative chart for these same data is called a clustered column (or bar) chart.

onsider the data below. What percentage of students scored grade C? Grades (Number of students) A (16) B (28) C (33) D (13) Total (90) a. 37% b. 28% c. 31% d. 33%

a. 37% A percent frequency distribution summarizes the percent frequency of the data for each bin. The percent frequency of a bin is the relative frequency multiplied by 100. 33/90 = 37%.

A data visualization tool that updates in real time and gives multiple outputs is called a. a data dashboard. b. a metrics table. c. a data table. d. the GIS.

a. a data dashboard. A data dashboard is a data visualization tool that illustrates multiple metrics and automatically updates these metrics as new data become available.

A chart that is recommended as an alternative to a pie chart is a a. bar chart. b. stacked column chart. c. box plot. d. line chart.

a. bar chart. Making visual comparisons is much easier in the bar chart than in the pie chart. It is recommended against using pie charts in most situations and suggested using bar charts for comparing categorical data instead.

If covariance between two variables is near 0, it implies that a. the variables are not linearly related. b. a positive relationship exists between the variables. c. the variables are negatively related. d. the variables are strongly related.

a. the variables are not linearly related. If the covariance between two variables is near 0, then the variables are not linearly related.

Compute the median of the following data. 32, 41, 36, 24, 29, 30, 40, 22, 25, 37 a. 34 b. 31 c. 40 d. 28

b. 31 The median is the value in the middle when the data are arranged in ascending order (smallest to largest value). The sorted data are 22, 24, 25, 29, 30, 32, 36, 37, 40, 41. ​ The median, in this case, is the average of the middle two values.

Use technology to c ompute the standard deviation for the following sample data. 32, 41, 36, 24, 29, 30, 40, 22, 25, 37 a. 5.96 b. 6.75 c. 5.42 d. 6.41

b. 6.75 The standard deviation is defined to be the positive square root of the variance and can be calculated using the Excel function =STDEV.S( ).

Which of the following graphs cannot be used to display categorical data? a. Clustered-column chart b. Scatter chart c. Pie chart d. Stacked-column chart

b. Scatter chart A scatter chart is a graphical presentation of the relationship between two quantitative variables. One variable is shown on the horizontal axis, and the other on the vertical axis.

Any data value with a z-score less than -3 or greater than +3 is considered to be a(n) a. statistic. b. outlier. c. z-score value. d. whisker.

b. outlier. Any data value with a z-score less than -3 or greater than +3 is treated as an outlier.

A __________ is used for examining data with more than two variables, and it includes a different vertical axis for each variable. a. column chart b. scatter plot c. PivotChart d. parallel-coordinates plot

d. parallel-coordinates plot One type of helpful chart for examining data with more than two variables is the parallel-coordinates plot, which includes a different vertical axis for each variable.

The goal regarding using an appropriate number of bins is to show the a. number of variables. b. correlation in the data. c. number of observations. d. variation in the data.

d. variation in the data. The goal is to use enough bins to show the variation in the data, but not so many classes that some contain only a few data items.