Question

3. Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places.

90% confidence; n = 480, x = 120

0.0325
0.0406
0.0348
0.0387

Answer 1

5. Use the given degree of confidence and sample data to construct a confidence interval for the population proportion p.

A survey of 865 voters in one state reveals that 408 favor approval of an issue before the legislature. Construct the 95% confidence interval for the true proportion of all voters in the state who favor approval.

0.438 < p < 0.505
0.444 < p < 0.500
0.471 < p < 0.472
0.435 < p < 0.508

Answer 2

9. Select the correct response.

Which estimator will consistently have an approximately normal distribution?

proportion
range
standard deviation
median

Answer 3

10. Provide an appropriate response.

Samples of size n = 60 are randomly selected from the population of numbers (0 through 9) produced by a random-number generator, and the mean is taken for each sample. What is the distribution of the sample means?

skewed to the left
not enough information provided
skewed to the right
normal (approximately)

Answer 4

11. Assume that a sample is used to estimate a population proportion p. Find the margin of error E that corresponds to the given statistics and confidence level. Round the margin of error to four decimal places.

99% confidence; n = 6500, x = 1950

0.0128
0.0146
0.0083
0.0111

Answer 5

13. Solve the problem.

The following confidence interval is obtained for a population proportion, p: (0.707, 0.745). Use these confidence interval limits to find the margin of error, E.

0.017
0.020
0.038
0.019

Answer 6

14.

Answer 7

15.

Answer 8

12.

Answer 9

I am sorry, I don't know satistics

Answer 10

I cant help either I'm afraid - I know some statistics but not this stuff.

Answer 11

do you know the central limit theorem?

Answer 12

Please here is what I know:
in physics, a random process, generally tends to a normal or gaussian distribution

Answer 13

ok i gotcha

Answer 14

for example one of those random process, is the so called:
"random walk", which I have studied when I was at my university inside the course of:
"structure of matter"

Answer 15

hm ok

Answer 16

seems interesting

Answer 17

another random process is the arrangement of a system of magnetic spins, in absence of external magnetic field

Answer 18

both of those random processes are well described by a gaussian distribution. I hope that my answer helps you

Answer 19

do you know how to work these though?

Answer 20

and yes i understood what you were saying

Answer 21

yes! I am able to perform computations with normal distribution

Answer 22

can you show me or tell me how to do these cause I need to do them

Answer 23

ok!

Answer 24

please I' trying to solve your problem, so wait please...

Answer 25

i am dont worry

Answer 26

mathmate and michele lets pull together what we know

Answer 27

In case Michele is working on #3, I will work on #5 to avoid interference and duplication.

Answer 28

ok and pitamar is studying how to o this

Answer 29

I will give hints rather than giving complete solution.
First you'll need to know what 95% confidence means, it's related to the normal distribution.

Answer 30

alright

Answer 31

Here's what you need to do for #5.
Go to http://www.stat.wmich.edu/s216/book/node70.html and find out how to find the standard error SE.

pHat is the proportion of the observed data, namely pHat=408/865=.471676.

To get 95% confidence, and the spread (up and down) from pHat, you need a multiplier for 95%, which is the 97.5% value of Z from the normal distribution table, i.e. P(pHat-Z*SE<p<pHat+Z*SE)=0.95.
You should find that Z(97.5)=1.645. If you don't ask, because you will need this skill for your next problems.

So the final range of p is
pHat-Z(97.5)*SE < p < pHat+Z(97.5)*SE.
It should correspond to one of the given answers.

Answer 32

ok let me try that for a mintue

Answer 33

Sure, give it a try.
If you succeed, I hope the remaining problems are similar.

Answer 34

ok it gave em one of them but i think id di it wrong

Answer 35

oops, sorry.
Z(95%)=1.645, for #3, but
Z(97.5%) =1.96 for #5.