Term
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Definition
A frequency table is a table with two columns. One column lists the categories, and
another for the frequencies with which the items in the categories occur (how many
items fit into each category). |
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Definition
A bar graph is a graph that displays a bar for each category with the length of each bar
indicating the frequency of that category. |
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Definition
| A Pareto chart is a bar graph ordered from highest to lowest frequency |
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Definition
A pie chart is a circle with wedges cut of varying sizes marked out like slices of pie or
pizza. The relative sizes of the wedges correspond to the relative frequencies of the
categories. |
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Term
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Definition
A pictogram is a statistical graphic in which the size of the picture is intended to
represent the frequencies or size of the values being represented. |
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Term
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Definition
| A histogram is like a bar graph, but where the horizontal axis is a number line |
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Term
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Definition
Class intervals are groupings of the data. In general, we define class intervals so that:
• Each interval is equal in size. For example, if the first class contains values from
120-129, the second class should include values from 130-139.
• We have somewhere between 5 and 20 classes, typically, depending upon the
number of data we’re working with. |
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Term
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Definition
An alternative representation is a frequency polygon. A frequency polygon starts out
like a histogram, but instead of drawing a bar, a point is placed in the midpoint of each
interval at height equal to the frequency. Typically the points are connected with
straight lines to emphasize the distribution of the data. |
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Term
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Definition
The mean of a set of data is the sum of the data values divided by the number of
values. |
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Term
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Definition
The median of a set of data is the value in the middle when the data is in order
To find the median, begin by listing the data in order from smallest to largest, or largest
to smallest.
If the number of data values, N, is odd, then the median is the middle data value. This
value can be found by rounding N/2 up to the next whole number.
If the number of data values is even, there is no one middle value, so we find the mean
of the two middle values (values N/2 and N/2 + 1) |
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Term
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Definition
| The mode is the element of the data set that occurs most frequently. |
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Definition
The range is the difference between the maximum value and the minimum value of the
data set. |
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Term
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Definition
The standard deviation is a measure of variation based on measuring how far each data
value deviates, or is different, from the mean. A few important characteristics:
• Standard deviation is always positive. Standard deviation will be zero if all the
data values are equal, and will get larger as the data spreads out.
• Standard deviation has the same units as the original data.
• Standard deviation, like the mean, can be highly influenced by outliers.
***To compute standard deviation:
1. Find the deviation of each data from the mean. In other words, subtract the mean
from the data value.
2. Square each deviation.
3. Add the squared deviations.
4. Divide by n, the number of data values, if the data represents a whole population;
divide by n – 1 if the data is from a sample.
5. Compute the square root of the result. |
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Term
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Definition
Quartiles are values that divide the data in quarters.
The first quartile (Q1) is the value so that 25% of the data values are below it; the third
quartile (Q3) is the value so that 75% of the data values are below it. You may have
guessed that the second quartile is the same as the median, since the median is the
value so that 50% of the data values are below it.
This divides the data into quarters; 25% of the data is between the minimum and Q1,
25% is between Q1 and the median, 25% is between the median and Q3, and 25% is
between Q3 and the maximum value |
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Term
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Definition
The five number summary takes this form:
Minimum, Q1, Median, Q3, Maximum
***To find the first quartile, Q1
Begin by ordering the data from smallest to largest
Compute the locator: L = 0.25n
If L is a decimal value:
Round up to L+
Use the data value in the L+th position
If L is a whole number:
Find the mean of the data values in the L
th and L+1th positions.
***To find the third quartile, Q3
Use the same procedure as for Q1, but with locator: L = 0.75n |
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Term
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Definition
A box plot is a graphical representation of a five-number summary.
To create a box plot, a number line is first drawn. A box is drawn from the first
quartile to the third quartile, and a line is drawn through the box at the median.
“Whiskers” are extended out to the minimum and maximum values. |
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Term
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Definition
| these are studies wherein subjects are observed to collect data. |
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Definition
| who or what are you interesting in learning about or gathering data about. |
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Term
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Definition
| will begin just as any other statistical study, in that the researcher will probably want to focus on some specific population; and then construct a representative sampling of that population. |
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Term
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Definition
| participants and perhaps the researchers interacting with the participants may not be aware of who is in which group |
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Term
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Definition
| is numerical data and more specifically data that we can perform calculations with. |
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Definition
| created to show patterns or trends of increase, decrease, or consistency over tim |
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Term
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Definition
| may also be used to display pairs of numerical data. However, neither variable will be a time unit counting from a start point. |
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Term
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Definition
| small part or quantity taken from a larger whole to show what the entire thing is like. |
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Term
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Definition
| A population is the total number of people or organisms living in a specific area. |
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Term
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Definition
| systemic error introduced into sampling or testing by selecting or encouraging one outcome or answer over others. |
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Definition
| Branch of math that deals with collecting analyzing interpreting and presenting data. |
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Term
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Definition
| measurable factor that defines a system or set the conditions of its operation. |
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Term
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Definition
| information in the form of facts or numbers that can be used to analyze and make decisions. |
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Definition
| A factor or characteristics that can change or vary often sued in experiments and data analysis, |
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Term
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Definition
| Statistical information about the characteristics of a population such as race, age, income and education. |
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Term
| Categorical (Or qualitative) data / variable |
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Definition
| data that can be divide into specific groups or categories such as gender hair color or types of food. |
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Definition
| information expressed in numbers |
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Definition
| Data that is categorized into group without any order or ranking. |
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Definition
| Data that can only take specific, separate values, often counted in whole numbers. |
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Definition
| Data that can take any value within a range and can be measured. |
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Definition
| A phenomenon where people experience real improvement in their condition after receiving a fake treatment simply because they believe it will work. |
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