Question

Using the standard Normal distribution tables, the area under the standard Normal curve corresponding to Z > –1.62 is
A. 0.0044.
B. 0.0526.
C. 0.9474.
D. 0.9956.

Answer 1

http://www.sjsu.edu/faculty/gerstman/EpiInfo/z-table.htm

Answer 2

I get 0.9474

Answer 3

1 - 0.9474 = 0.0526 so B?

Answer 4

@lgbasallote

Answer 5

looks good to me, you got it

Answer 6

:)

Answer 7

oh wait, the table represents positive values of z and not negative values (just noticing this)

So the answer is actually 0.9474

Answer 8

look @ bottom it shows how to get negs?

Answer 9

seems like to get a neg yo do 1- #

Answer 10

This table computes the area to the left of z = k (where k is positive)

Since the standard normal distribution is symmetric about 0, this means

P(Z > -1.62) = P(Z < 1.62)

which shows us that the answer is 0.9474

Answer 11

1.62 = 9474 check the bottom it explains it.

Answer 12

A useful trick to remember is that

P(Z > -k) = P(Z < k) for some number k

Answer 13

z 9750 = 1.96 z 250 = -1.96 :p

Answer 14

I see that, but the answer is still 0.9474

Answer 15

>(?

Answer 16

wolfram even confirms it

http://www.wolframalpha.com/input/?i=normalcdf%28-1.62%2C10%29

Answer 17

look 1 above it... 0.526

Answer 18

since it's Z> then I gess yo'r right...

Answer 19

>(

Answer 20

no, the answer you want is in the last row of that table in wolfram alpha

Answer 21

so if it said z = 0.250 wold I have been correct?

Answer 22

where it says -1.62 < z < 10

Answer 23

you mean P( Z < 0.250) ?

Answer 24

I see this is tricky...

Answer 25

I'm konfused what the table is showing 4 the neg? z 9750 = 1.96 z 250 = -1.96 :??? When do we use this?

Answer 26

Using the standard normal distribution tables, the area under the standard Normal curve corresponding to –0.5 < Z < 1.2 is
A. 0.3085.
B. 0.8849.
C. 0.5764.
D. 0.2815.
this is actally the next q :)

Answer 27

the 0.9750 is the area to the left of the curve, the 1.96 is the z-score

so

z 9750 = 1.96

means

P(Z < 1.96) = 0.9750)

Answer 28

and what abot the neg? part? -1.96

Answer 29

if you have a negative, you can flip it so to speak, by using the idea that this distribution is symmetrical about 0

So that's why they're subtracting 0.9750 from 1 to get 0.0250

Answer 30

The rule they are using is this

P(Z > -k) = P(Z < k) for some positive number k

Answer 31

yes thats what I was saying....

Answer 32

so in this case since they as x<z<y we have to select the pos value?

Answer 33

if it wanted z = -1.69 then we cold have bused the other one?

Answer 34

or shold I say Z>

Answer 35

not sure where you're getting -1.69

Answer 36

z< -1.96

Answer 37

oh ok

Answer 38

err

-1.62

Answer 39

they buse 1.96 :P

Answer 40

if you wanted to find P(Z > -1.62)

then you would use the trick above to get P(Z < 1.62), from there, you'd use the table

Answer 41

Ah I see how this i snow I had to look at it again.. So Z < 1.62 only ntil -1.62 ho...

Answer 42

P(Z < 1.62), wold give the same answer?

Answer 43

yes, P(Z > -1.62) and P(Z < 1.62) are equivalent

Answer 44

I mean on the table 1.62 is 1.62 doesn't matter if it's P(Z < 1.62), or P(Z < -1.62),

Answer 45

oh, it's positive

Answer 46

or does one yeild one half and the other the other half? Like the .975 and .025

Answer 47

so it's just P(Z < 1.62)

Answer 48

it's always one or the other? no Z = 1.62?

Answer 49

well if Z > 1.62 we have an isse

Answer 50

no, you can't compute the area from 1.62 to 1.62...that doesn't make any sense

Answer 51

what?

Answer 52

if you want Z > 1.62, then find Z < 1.62 and subtract that from 1

Answer 53

ic. os if it's above or below IC G|< Z < |G it will be 1- #?

Answer 54

now we are getting somewhere

Answer 55

in this next Q

Using the standard normal distribution tables, the area under the standard Normal curve corresponding to –0.5 < Z < 1.2 is
A. 0.3085.
B. 0.8849.
C. 0.5764.
D. 0.2815.

We need to do it 2x right? once 4 -0.5 and once 4 1.2? :)

Answer 56

or Idk since it's 1 answer.

Answer 57

–0.5 < Z < 1.2

is the same as

–0.5 < Z and Z < 1.2

Answer 58

I thoght abot sing both on the table.

Answer 59

which turns into

Z > -0.5 and Z < 1.2

Answer 60

0.5199 &0.8849

Answer 61

0.8849 = B

Answer 62

There might be more to this Q tho....

Answer 63

actally above 0.5 is

Answer 64

0.4801

Answer 65

Z < 0.5 is 0.6915

Answer 66

So P( Z > -0.5) = 0.6915

Answer 67

oh crap I looked @ 0.05 HAAHAH

Answer 68

0.6915 isn't there so is it B?

Answer 69

Now use the rule

P(a < Z < b) = P(Z < b) - P(Z < a)

Answer 70

I was thinking that bt it woldonly be .1....?

Answer 71

0.1934

Answer 72

P(a < Z < b) = P(Z < b) - P(Z < a)

P(-0.5 < Z < 1.2) = P(Z < 1.2) - P(Z < -0.5)

P(-0.5 < Z < 1.2) = P(Z < 1.2) - P(Z > 0.5)

P(-0.5 < Z < 1.2) = P(Z < 1.2) - [ 1 - P(Z < 0.5) ]

P(-0.5 < Z < 1.2) = 0.8849 - [ 1 - 0.6915 ]

P(-0.5 < Z < 1.2) = 0.8849 - [ 0.3085 ]

P(-0.5 < Z < 1.2) = 0.5764

Answer 73

where does that 1 come bfrom?

Answer 74

oic why is itdiff bfrom the prev answer...?

Answer 75

oh I see format...

Answer 76

thanks :)

Answer 77

http://openstudy.com/study#/updates/505cf41be4b0583d5cd15dea next q's!!!! :)

Answer 78

yeah it's a bit messy, but you at least see all the nitty gritty details

Answer 79

sry i have to get going

Answer 80

yeah I'm glad I learned this.

Answer 81

Oh okay >(. I think I'm correct, no one's verifying me :(

Answer 82

you at least have wolfram alpha to check your work

Answer 83

do you know how to use it?

Answer 84

thanks again!! yeah I'm not sre how

Answer 85

calc 2 I doo, not stats..

Answer 86

type

normalcdf(a,b)

and replace 'a' and 'b' with any numbers you want (where a < b)

Examples:

normalcdf(1,2) computes P( 1 < Z < 2)

normalcdf(-0.5,1.2) computes P( -0.5 < Z < 1.2)

normalcdf(2,10) computes P( 2 < Z < 10) ...which is basically the same as P( Z > 2)

Answer 87

what abot mean and standard deviation?

Answer 88

you can either

a) convert each raw score to a standard z score

or

b)

type

normalcdf(a,b,mu,sigma)

which will compute P( a < X < b) with mean mu and standard deviation sigma

if you leave off mu and sigma, wolfram alpha will use the default mu = 0 and sigma = 1

Answer 89

okay :) thanks :)

Answer 90

np