Question

PLZ HELP!!! See attachment.

Answer 1

@Luis_Rivera so i'll take that as you don't know how to do it?

Answer 2

@amistre64 can you help with this?

Answer 3

which part is giving you room to pause?

Answer 4

all of it

Answer 5

lets work on the test stat first, what do you recall about computing a tscore?

Answer 6

\[t=\frac{\bar x-\mu}{s}\sqrt n\]

Answer 7

oh ok i thought that was the formula but i wasn't sure.

Answer 8

#3 suggests that you recall something about hypt testing to begin with

if we are looking for < or > its in a tail; if we are looking for =, its in both tails

Answer 9

When you say #3 you mean question c)?

Answer 10

part d, or #4 (i thought they was numbered) would suggest that the red is inbetween 2 values ...

Answer 11

for b) i did \[\frac{ 102.0-105 }{ \frac{ 5.8 }{ \sqrt{35} } }\] =-0.09

Answer 12

your setup is correct, but your calculation is off

Answer 13

i put it into mathway and it came out as 0.0874. so that makes it 0.09 right?

Answer 14

102-105 = -3

-3/5.8 = -0.51724

-0.51724 * sqrt(35) = -3.060...

Answer 15

so the answer would be -3.06?

Answer 16

thats what my ti83 gives me, yes

Answer 17

the standard deviation is 5.8/sqrt(35); or about .98

we are 3 to the left of center, giving us a little over -3 sds away

Answer 18

i'm getting something different.
102.0-105=-3
-3/5.8=-0.5172413793
-0.5172413793/sqrt(35)=-0.08742975049=-0.09

Answer 19

your not spose to divide that by sqrt(35)

Answer 20

\[\frac{a}{p/q}=\frac{a}{p}*q\]

Answer 21

if anything, 5.8/sqrt(35) = .98

-3/.98 = -3.06

Answer 22

ok i see that now.

Answer 23

part c has me a little confused, my book is stating a path:

type of test? two tailed (since H0 not= H1 hyp)
tstat to the left of right? ours is left since its negative
therefore Pvalue = 2x the area to the left of the t score

Answer 24

its twice the area since its 2 tailed ... got it

Answer 25

so c) is B?

Answer 26

thats what i had originally considered, and thats what im going with :)

Answer 27

ok
Is a) B?

Answer 28

my gut says no. but quite frankly i never was good at that kind of question. I want to say it yes, but cant really say why

Answer 29

well whats you're gut say it is?

Answer 30

my gut likes d, but its lied to me before :)

on c, my book shows the pvalue area redshaded to the left, and says the pvalue is twice the area shaded ... which has me thinking that c is also just left shaded

Answer 31

then i will go with that. :)

Answer 32

now d)

Answer 33

how do you normally find the area? ti83 by chance?

Answer 34

no by hand or google

Answer 35

well, our zscore is -3.06 :) and we want the area to the left of it

Answer 36

so that would be...?

Answer 37

i thought you had indicated that you could find that area .... by hand or by google

Answer 38

http://www.danielsoper.com/statcalc3/calc.aspx?id=2

Answer 39

that's confusing.
1.25 means...?

Answer 40

1.25 is just a primer, our z score we found is -3.06

enter it into the box and hit calculate, it will give you the cumulative area up to z = -3.06

Answer 41

it gave me 0.00110668

Answer 42

im thinking that this is the lower bound, the area that is in the "red" we want to double that for an upper bound.

Answer 43

i'm thinking d) is A

Answer 44

...me too, but then again im only going off of what im reading in my stats book. if in reading it incorrectly, then i cant really guarentee the accuracy of my "guidance"

Answer 45

my ti83 gives a T-test, p-value of .004, which is not a range like the options .... nor is it really in the range of .001 to .002 ....

Answer 46

of course that next question has alot of 4s in it

.004 * 1000 = 4

Answer 47

ok that means...?

Answer 48

at the moment, that means im conflicted between what the book says, and what the overall problem set is telling us.

if p = .004, that would suggest that our range is between 002 and 005, but thats not the results i get from doing the process in the book. I simply dont have enough experience at this to know what, if anything, i am doing wrong :/

Answer 49

well whats your best guess?

Answer 50

i'd go with the book.

Answer 51

lol, the book doesnt jive with the next problem tho, so im thinking ive missed something.

ti83 and the test stat by hand each give us -3.06

this should be the zscore value as well, unless there is some z to t adjustment that im missing

Answer 52

lol well i'll take a guess cause this problem is giving me a headache. lol

Answer 53

give me about 10 minutes to review a youtube :)

Answer 54

lol ok

Answer 55

got it

Answer 56

we should not have used the "normal" distribution with a t-score

Answer 57

when i use the tCDF, with 1 degree of freedom:

tCDF(-9999,-3.06,35-1) = .00215

and doubled is .00430

Answer 58

?

Answer 59

in short, i assumed the t = z .... so our Pvalue is between .0021 and .0043

Answer 60

this will correspond to the next problem

Answer 61

so c) is C?

Answer 62

im going with C, yes :)

Answer 63

so to Interpret that it would be...?

Answer 64

well, to guide you to this, we just tested a mean of 102, and it has a Pvalue (probability value) of .4 % .... or .4 in every 100

how would you use this to determine (d) ?

Answer 65

if you expected to be paid: .004 cents for every hour you worked

how much would you make in 10 hours? in 100? in 1000?

Answer 66

.004*10?

Answer 67

yes, so .04 cents for 10 hours ...

and for 100?

Answer 68

0.4

Answer 69

good, 100 for .4 match an option? or do we need to go to 1000?

Answer 70

well 1000 is 4

Answer 71

so, its either B or C

notice that the name on our little paycheck is "102" since thats what this Pvalue is attributed to

Answer 72

we should expect that in 1000 hours, mister 102 will be paid 4

Answer 73

so it's C?

Answer 74

gut says C :)

Answer 75

good now e)

Answer 76

(e) has to do with something im more familar with, a confidence interval

Answer 77

the area to reject the is termed alpha, that a looking thing

Answer 78

the expected value of a = .01
our pvalue is at best: .004

we rejecct the null hypotheses if the pvalue is less then or equal to the "a" value

Answer 79

so it's yes?

Answer 80

correct

Answer 81

Great! got time to help with 1 more short question?

Answer 82

not really, i have to be heading home.

Answer 83

lol ok thx for the help!

Answer 84

good luck with this :)

Answer 85

THX!