# Connexions

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### Lenses

What is a lens?

#### 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.

#### In these lenses

• 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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### Tags

(What is a tag?)

These tags come from the endorsement, affiliation, and other lenses that include this content.

Inside Collection (Textbook):

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

# Review

The next two questions refer to: X X ~ U ( 3 , 13 ) U(3,13)

## Exercise 1

Explain which of the following are false and which are true.

• a: f(x)=110f(x)=110 size 12{f $$x$$ = { {1} over {"10"} } } {}, 3x133x13 size 12{3 <= x <= "13"} {}
• b: There is no mode.
• c: The median is less than the mean.
• d: P ( x > 10 ) = P ( x 6 ) P ( x > 10 ) = P ( x 6 ) size 12{P $$x>"10"$$ =P $$x <= 6$$ } {}

### Solution

• a: True
• b: True
• c: False – the median and the mean are the same for this symmetric distribution
• d: True

## Exercise 2

Calculate:

• a: Mean
• b: Median
• c: 65th percentile.

### Solution

• a: 8
• b: 8
• c: P(x<k)=0.65=(k3)(110)P(x<k)=0.65=(k3)(110) size 12{P $$x<k$$ =0 "." "65"= $$k - 3$$ * $${ {1} over {"10"} }$$ } {}. k=9.5k=9.5 size 12{k=9 "." 5} {}

## Exercise 3

Which of the following is true for the above box plot?

• a: 25% of the data are at most 5.
• b: There is about the same amount of data from 4 – 5 as there is from 5 – 7.
• c: There are no data values of 3.
• d: 50% of the data are 4.

### Solution

• a: False – 3434 size 12{ { {3} over {4} } } {} of the data are at most 5
• b: True – each quartile has 25% of the data
• c: False – that is unknown
• d: False – 50% of the data are 4 or less

## Exercise 4

If P(GH)=P(G)P(GH)=P(G) size 12{P $$G \lline H$$ =P $$G$$ } {}, then which of the following is correct?

• A: GG size 12{G} {} and HH size 12{H} {} are mutually exclusive events.
• B: P ( G ) = P ( H ) P ( G ) = P ( H ) size 12{P $$G$$ =P $$H$$ } {}
• C: Knowing that HH size 12{H} {} has occurred will affect the chance that GG size 12{G} {} will happen.
• D: GG size 12{G} {} and HH size 12{H} {} are independent events.

D

## Exercise 5

If P(J)=0.3P(J)=0.3 size 12{P $$J$$ =0 "." 3} {}, P(K)=0.6P(K)=0.6 size 12{P $$K$$ =0 "." 6} {}, and JJ size 12{J} {} and KK size 12{K} {} are independent events, then explain which are correct and which are incorrect.

• A: P( J and K)P( J and K) = 0 = 0
• B: P( J or K) = 0.9P( J or K) = 0.9
• C: P( J or K) = 0.72P( J or K) = 0.72
• D: P ( J ) P (J K) P ( J ) P (J K)

### Solution

• A: False - J and K are independent so they are not mutually exclusive which would imply dependency (meaning P(J and K) is not 0).
• B: False - see answer C.
• C: True - P(J or K) = P(J) + P(K) - P(J and K) = P(J) + P(K) - P(J)P(K) = 0.3 + 0.6 - (0.3)(0.6) = 0.72. Note that P(J and K) = P(J)P(K) because J and K are independent.
• D: False - J and K are independent so P(J) = P(J|K).

## Exercise 6

On average, 5 students from each high school class get full scholarships to 4-year colleges. Assume that most high school classes have about 500 students.

XX = the number of students from a high school class that get full scholarships to 4-year school. Which of the following is the distribution of XX?

• A. P(5)
• B. B(500,5)
• C. Exp(1/5)
• D. N(5, (0.01)(0.99)/500)

A

## Content actions

PDF | EPUB (?)

### What is an EPUB file?

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

#### Collection 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

#### 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