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Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

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• Lucy Van Pelt

This collection is included inLens: Lucy's Lens
By: Tahiya Marome

"Part of the Books featured on Community College Open Textbook Project"

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• Bio 502 at CSUDH

This collection is included inLens: Bio 502
By: Terrence McGlynn

"This is the course textbook for Biology 502 at CSU Dominguez Hills"

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Inside Collection (Textbook):

Textbook by: Barbara Illowsky, Ph.D., Susan Dean. E-mail the authors

Summary of Formulas

Summary: A summary of useful formulas used in examining descriptive statistics

Commonly Used Symbols

• The symbol ΣΣ means to add or to find the sum.
• nn = the number of data values in a sample
• NN = the number of people, things, etc. in the population
• x¯x¯ size 12{ {overline {x}} } {} = the sample mean
• ss = the sample standard deviation
• μμ = the population mean
• σσ = the population standard deviation
• ff = frequency
• xx = numerical value

Commonly Used Expressions

• x*fx*f = A value multiplied by its respective frequency
• xx size 12{ Sum {x} } {} = The sum of the values
• x*fx*f size 12{ Sum {x} times f} {} = The sum of values multiplied by their respective frequencies
• ( x x ¯ ) (x x ¯ ) or ( x μ ) (xμ) = Deviations from the mean (how far a value is from the mean)
• ( x x ¯ ) 2 ( x x ¯ ) 2 or ( x μ ) 2 ( x μ ) 2 = Deviations squared
• f ( x x ¯ ) 2 f ( x x ¯ ) 2 or f ( x μ ) 2 f ( x μ ) 2 = The deviations squared and multiplied by their frequencies

Mean Formulas:

• x¯=x¯= size 12{ {overline {x}} ={}} {}xnxn size 12{ { { Sum {x} } over {n} } } {} or x¯=x¯= size 12{ {overline {x}} ={}} {}f· xnf· xn size 12{ { { Sum {f times x} } over {n} } } {}
• μ=μ= size 12{μ={}} {}xNxN size 12{ { { Sum {x} } over {N} } } {} or μμ size 12{μ} {}= f·xNf·xN size 12{ { { Sum {f times x} } over {N} } } {}

Standard Deviation Formulas:

• s=s= size 12{s={}} {} Σ ( x x ¯ ) 2 n 1 Σ ( x x ¯ ) 2 n 1 or s=s= size 12{s={}} {} Σ f · ( x x ¯ ) 2 n 1 Σ f · ( x x ¯ ) 2 n 1
• σ=σ= size 12{σ={}} {} Σ ( x μ ¯ ) 2 N Σ ( x μ ¯ ) 2 N or σ=σ= size 12{σ={}} {} Σ f · ( x μ ¯ ) 2 N Σ f · ( x μ ¯ ) 2 N

Formulas Relating a Value, the Mean, and the Standard Deviation:

• value = mean + (#ofSTDEVs)(standard deviation), where #ofSTDEVs = the number of standard deviations
• xx size 12{x} {} = x¯ x + (#ofSTDEVs)(ss)
• xx size 12{x} {} = μμ size 12{μ} {} + (#ofSTDEVs)(σσ)

Content actions

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What is an EPUB file?

EPUB is an electronic book format that can be read on a variety of mobile devices.

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My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

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Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks

Module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags?

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks