QA- Unit 1

Which correlation coefficient suggests the strongest relationship?

+1

With symmetric, "bell-shaped" distributions, approximately what percent of the observations are within two standard deviations of the mean?

95%

The four areas of a pivot table are

Filters, Rows, Columns, and Values.

What is the most common type of chart for showing the distribution of a numerical variable?

Histogram

Which of the following characteristics can be used to describe the skewness of a distribution?

Kurtosis

What does a scatterplot illustrate?

What type of relationship there is between two variables

Scatterplots are also referred to as

X-Y charts

If the number of observations in a single-variable data set is even, the median is the

average of the two middle observations

Categorizing a numeric age variable as "young," "middle-aged," and "elderly" is an example of

binning

Displaying all correlations between 0.6 and 0.999 on a scatterplot as green and all correlations between -1.0 and -0.6 as red is known as _____ formatting.

conditional

Which of the following are considered numerical summary measures?

correlation and covariance

To examine relationships between two categorical variables, we can use

counts and corresponding charts of the counts.

A sample, selected from a population, taken at one particular point in time is categorized as

cross-sectional

The tables of counts that result from pivot tables are often called

crosstabs

Data that arise from counts are best described as _____ data.

discrete

The average score for a class of 30 students was 75. The 20 male students in the class averaged 70. The average score of the 10 female students in the class is _____ the males.

greater than

Where will you find "time" on a time series graph?

horizontal axis

The difference between the first and third quartile is called the

interquartile range

The length of the box in the box plot portrays the

interquartile range

The limitation of covariance as a descriptive measure of association is that it

is very sensitive to the units of the variables.

In a box plot, the asterisk inside the box indicates the location of the

mean

The median can also be described as the

middle observation when the data values are arranged in ascending order

The mode is best described as the

most frequently occurring value

Excel® stores dates as

numbers

In order for the characteristics of a sample to be generalized to the entire population, the sample should be _____ the population.

representative of

Researchers may try to gain insight into the characteristics of a population by examining a(n) _____ from the population.

sample

A histogram that is positively skewed may also be described as

skewed to the right

The most common data format is

stacked

Correlation and covariance measure the

strength and direction of a linear relationship between two numerical variables.

A variable is classified as ordinal if

there is a natural ordering of categories

The daily closing values of the Dow Jones Industrial Average over a period of 30 days are best described as _____ data.

time-series

Without performing any calculations, which of the following data sets has the greatest sample standard deviation?

1,1,1,5,5,5

The mean of a data set is 75 and one observation has the value of 65. What is the squared deviation of the observation, 65, from the mean?

100

Expressed in percentiles, the interquartile range is the difference between the _____ percentiles.

25th and 75th

Examples of comparison problems include

All of these choices are correct

Which Excel® function allows you to count using more than one criterion?

COUNTIFS

The interquartile range (IQR) encompasses what percent of the observations?

Middle 50%

Which measure of variability is defined as the maximum value of a data set minus the minimum value of a data set?

Range

Which statement is true for the following data values: 7, 5, 6, 4, 7, 8, and 12?

The mean, median, and mode are all equal

A useful way of comparing the distribution of a numerical variable across categories of some categorical variable is with

a side-by-side plot or side-by-side pivot table.

Gender and states of residence are examples of ____ data.

categorical

We can infer that there is a strong relationship between two numeric variables when the points on a scatterplot

cluster tightly around a straight line.

Coding males as 1 and females as 0 in a data set illustrates the use of _____ variables.

dummy

One characteristic of "paired variables" is that

each variable has the same number of observations

Tables used to display counts of a categorical variable are called

either crosstabs or contingency tables.

If a value represents the 95th percentile, this means that 95% of all values in the data set are _____this value.

less than or equal to

What are the three most common measures of central tendency?

mean, median, mode

Correlation is useful only for

measuring the strength of a linear relationship

In a box plot, the vertical line inside the box indicates the location of the

median

We study relationships among numerical variables using

percentages

The tool that provides useful information about a data set by breaking it down into categories is a

pivot table

Changing the location of fields in a pivot table is known as

pivoting

If the correlation of variables is close to 0, then we expect to see a(n) _____ on the scatterplot.

random scatter of points with no apparent relationship

A line or curve superimposed on a scatterplot to quantify an apparent relationship is known as a(n)

trend line.