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/sci/ - Science & Math

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1168092 No.1168092 [Reply] [Original]

Anyone good at stats? I cant seem to figure any of this out...

1. A recent survey reported in USA Today Snapshots found that 77% of American travelers purchase plane tickets on the Web. Suppose the survey was based on 1000 respondents.

a) Construct a 95% confidence interval estimate for the population of American travelers who purchase plane tickets on the Web.

b) Would a 90% confidence interval be wider or narrower than the 95% confidence interval? Explain.

2. A restaurant owner claims that the average wait-time for a table is less than 8 minutes. To check her claim a reporter from a local newspaper records the wait-times for 15 restaurant customers selected at random. The wait times were

3.90 5.90 8.02 5.79 8.73 7.82 6.60 10.49
6.68 5.64 6.20 6.17 9.91 7.00 8.35

a) Assume that the population of wait-times is normally distributed and test the owners claim at the 0.95 level of confidence.

b) Why is it necessary to be told that the population of wait-times is normally distributed?

>> No.1168118

homeworks?

>> No.1168125

Oh sure anon.

Do this:

DO YOUR OWN FUCKING HOMEWORK.

:)

>> No.1168147

Its homework and if I can do it by myself I wouldn't be wasting time here trying to get help would I? Not all of us are lazy it just that I spend 1 hour reading this dam question and I have no clue

>> No.1168155

>>1168125
I think this board would be better if we actually HELPED people with homework threads.

All this "fuckoff no homework threads" screams to me that the poster has no idea how to solve the question and just wants to be an unhelpful dick.

OP, if I knew how to help you with this, I would.

>> No.1168164

>>1168155

If we did, this board would become HW central for lazy fucks that don't want to do anything or learn shit--they just want the stupid credit.

>> No.1168167 [DELETED] 

>>1168088
www.anomtalk.se but with n instead of m near the middle 7a76b9b40b1fe53502bcea1499d13f55 80145

>> No.1168169

Forgot to do this.

>> No.1168170

>>снайпер

Thanks

>> No.1168214

1a. 2.61
1b. wider.

>> No.1168226

2a. find the mean and the sample size. plug it in.
2b. confidence intervals only work on a normal distribution.

>> No.1168242

>>1168226
>>1168214

Thanks, am going to try and plug in some numbers see what I get

>> No.1168270

>>1168242
1b. actually, it will be narrower. i was thinking backward. the center part of the distribution will be narrower.