Question

Help!!!
The mean score on a biology exam taken by all undergraduate students in a college in a particular year is 67.8 with a standard deviation of 11.5.
The standard error of the mean for a sample of 70 students is ?
and the margin of error of the mean is ?

Answer 1

@jim_thompson5910 can u help me please

Answer 2

ill help hold on

Answer 3

does this help
http://openstudy.com/study#/updates/51d9da2fe4b015ed7421cd72

Answer 4

thanks but still confused

Answer 5

do i find the z score first?\
z=1E+300
i cant remember it this is right.
I thought I was to set it up like a fraction/squareroot

Answer 6

@SolomonZelman can u help me

Answer 7

sorry had to do something 4 my dad

Answer 8

its ok

Answer 9

hold on im looking at what you said do you have answer choices

Answer 10

it would make this alot easier

Answer 11

i will explain the answer

Answer 12

come on i have to go soon

Answer 13

ok

Answer 14

i have 5 min

Answer 15

no I dont have answer choices im pretty sure there is a equation i follow I just cant remember it

Answer 16

to find mean add all the #'s and divide by however many there are

Answer 17

so I add the mean +standard deviation + the sample and then divide? by what

Answer 18

yes just likke that

Answer 19

divide by 3

Answer 20

No I already have the mean its given in the word problem. Its 67.8

Answer 21

that looks righht

Answer 22

lol no thats not right but thanks

Answer 23

oh i see what is the difference in the error and what u got

Answer 24

70-67.8=2.2

Answer 25

i gtg 1 min

Answer 26

70 is my sample

Answer 27

where do I calculate my z score

Answer 28

what math r u in this seems very complicated do u have to get this done tonight

Answer 29

ALG2/statistics

Answer 30

no just trying to get as much done because i have exams soon

Answer 31

that y im in algebra1 can i do this with u in the morning

Answer 32

ok cool thanks!

Answer 33

i gtg now basically np what time u wanna do it

Answer 34

its 935 here in florida

Answer 35

anytime i'll be on and off all morning

Answer 36

oh ok ill be there i fanned you too so ill know when ur on

Answer 37

936 here in florida haha

Answer 38

oh ok we both r floridians sorry some people here have different times so its very confusing just had to say it

Answer 39

ok and yeah I know thanks :)

Answer 40

np ttyl gn bye

Answer 41

bye

Answer 42

so for the standard error it would be 11.5/sqrt(70) = 1.3745 = 1.37
now I need to find the margin of error of the mean??
HELP!!!

Answer 43

@Sepeario can you help me?

Answer 44

@thepotatoking81 can u help

Answer 45

Desired confidence level?

Answer 46

have no clue.

Answer 47

lol I wish I had a high confidence level. :)
just kidding I need to find the confidence level?

Answer 48

The confidence level should be given.

Answer 49

Its not
dont I need to find the critical value?
margin of error = critical value * standard error
Is this right? My brain will explode :P

Answer 50

Yes but what is the critical value? Confidence interval can be converted to critical value.

Answer 51

0.1

Answer 52

critical value is z score?

Answer 53

sqrt((1.37/70*(0.1-1.37))/70 would this be correct?

Answer 54

If the z-score is 0.1, then 0.1 x standard error = margin of error.

Answer 55

"sqrt((1.37/70*(0.1-1.37))/70"
I have no idea what you are doing here.

Answer 56

so my standard error and margin of error is the same?

Answer 57

was my z-score correct?

Answer 58

sorry I have been trying to figure this out since yesterday

Answer 59

@ikram002p can u check this for me?

Answer 60

The standard error of the mean for a sample of 70 students is ? 1.37
and the margin of error of the mean is ? 1.37
Can some one check this for me and see if it is correct?
@jdoe0001 or @amistre64 please

Answer 61

The mean score on a biology exam taken by all undergraduate students in a college in a particular year is 67.8 with a standard deviation of 11.5.

The standard error of the mean for a sample of 70 students is ?

sqrt(sd^2/n) sqrt(11.5^2/70) is about 1.37, thats good




and the margin of error of the mean is ?

margin of error should be in reference to some level of confidence, it has a z score related to it so that the margin of error is z(1.37)

Answer 62

as is, i dont know what they would refer to as a margin of error value since no interval width is suggested

Answer 63

Is that the confidence?

Answer 64

oh, maybe the difference from the population mean

Answer 65

we arent given any menas other than the population to start with so we have nothing to compare

Answer 66

the population being the 70

Answer 67

the sample size is 70, there is no sample mean given that i can determine

Answer 68

did I have the correct z score

Answer 69

o.1

Answer 70

1.37 is not a z score, its a standard error for the sample size.

Answer 71

yes I understand that

Answer 72

the z score is related to some interval width ... no width is given

Answer 73

but when you find the margin of error i need to know that correct

Answer 74

yes

standard error = sqrt(variance/sample size)
SE = sqrt(sd^2/n)

margin of error is jsut the number of standard errors that we want for be comfortable with:
z(SE)

Answer 75

if we want to be 68% confident that the population mean is within some interval of a sample mean, the z=1

Answer 76

well, approximately 1

Answer 77

but they don't give me a percentage to compare. sorry confused

Answer 78

we would expect 95% of the sample means of sample size 70 to be within z=2 of the population mean

67.8 +- 2(1.37) = an interval of 65.06 to 70.54

Answer 79

i know, hence my aversion to say if you are correct or not :)

Answer 80

it may be best to consult your course material for a similar example

Answer 81

i think I would bet on you better than me lol

Answer 82

so my standard deviation is most likely wrong

Answer 83

your standard error is fine. its the margin of error that makes no sense without further clarification.

Answer 84

ok thanks for helping me. probably another faulty question.

Answer 85

I really appreciate it. I have been trying to figure this out for days.

Answer 86

see, we need a z value to associate a margin of error with

Answer 87

got it thanks again!

Answer 88

Yea I checked back and that's how the question reads. :/