descriptive statistical Flashcards
What is descriptive statistics?
Descriptive statistics is a branch of statistics that deals with summarizing and organizing data.
True or False: Descriptive statistics can infer conclusions about a population from a sample.
False
What are the two main types of descriptive statistics?
Measures of central tendency and measures of variability.
Fill in the blank: The three measures of central tendency are mean, median, and _____.
mode
What is the mean?
The mean is the average of a set of numbers, calculated by dividing the sum of the values by the number of values.
How is the median determined?
The median is the middle value when the data set is ordered from least to greatest.
What is the mode?
The mode is the value that appears most frequently in a data set.
True or False: A data set can have more than one mode.
True
What is a frequency distribution?
A frequency distribution is a summary of how often each value occurs in a data set.
What does a histogram represent?
A histogram represents the frequency distribution of numeric data using bars.
What is the range of a data set?
The range is the difference between the maximum and minimum values in a data set.
What are quartiles?
Quartiles are values that divide a data set into four equal parts.
What is the interquartile range (IQR)?
The interquartile range is the difference between the first and third quartiles (Q3 - Q1).
True or False: The standard deviation is a measure of how spread out the values in a data set are.
True
What is variance?
Variance is the average of the squared differences from the mean.
What does a box plot represent?
A box plot represents the distribution of a data set based on five summary statistics: minimum, first quartile, median, third quartile, and maximum.
Fill in the blank: In a box plot, the line inside the box represents the _____.
median
What is a percentile?
A percentile is a measure indicating the value below which a given percentage of observations in a group of observations falls.
What is the purpose of descriptive statistics?
The purpose of descriptive statistics is to summarize and describe the main features of a data set.
True or False: Descriptive statistics can be used for inferential purposes.
False
What type of data is best suited for a pie chart?
Categorical data.
What is a scatter plot used for?
A scatter plot is used to determine the relationship between two quantitative variables.
Fill in the blank: The ____ is the sum of all data points divided by the number of points.
mean
What does the term ‘skewness’ refer to?
Skewness refers to the asymmetry of the distribution of values in a data set.
True or False: A positively skewed distribution has a longer tail on the right side.
True
What is kurtosis?
Kurtosis is a measure of the ‘tailedness’ of the probability distribution of a real-valued random variable.
What is a cumulative frequency distribution?
A cumulative frequency distribution shows the cumulative total of frequencies up to a certain point.
Fill in the blank: The ____ of a data set is the value that occurs most frequently.
mode
What is the difference between population and sample in statistics?
A population includes all members of a specified group, while a sample is a subset of the population.
What is a dot plot?
A dot plot is a simple graphical display that uses dots to represent the frequency of values in a data set.
True or False: Descriptive statistics can help identify outliers in data.
True
What is the purpose of using measures of central tendency?
To summarize a data set with a single representative value.
What is a stem-and-leaf plot?
A stem-and-leaf plot displays quantitative data while preserving the original data values.
Fill in the blank: The ____ is a measure that provides an idea of the average distance of data points from the mean.
standard deviation
What is the relationship between variance and standard deviation?
Standard deviation is the square root of variance.
What does a normal distribution look like?
A normal distribution is bell-shaped and symmetric about the mean.
True or False: In a normal distribution, approximately 68% of the data falls within one standard deviation of the mean.
True
What is a frequency polygon?
A frequency polygon is a graphical representation of the frequency distribution of a dataset using line segments.
Fill in the blank: The ____ of a data set is calculated as the square root of the variance.
standard deviation
What is a bar graph used for?
A bar graph is used to compare different categories of data.
What does a negative skew indicate?
A negative skew indicates that the left tail of the distribution is longer or fatter than the right tail.
What is a z-score?
A z-score indicates how many standard deviations a data point is from the mean.
Fill in the blank: A ____ is a visual display of the distribution of data points in a data set.
histogram
What is a two-way table?
A two-way table is used to summarize data that involves two categorical variables.
True or False: The mean is always a better measure of central tendency than the median.
False
What is a potential drawback of using the mean?
The mean can be heavily influenced by outliers.
What type of data is best suited for a bar graph?
Categorical data.
What is a scatter plot used for?
To show the relationship between two quantitative variables.
