The Paired-Difference t Procedure

[@samad.chouihat4222]

the best statistics channnel ever . thnks for the help. greeting from algeria

[@Basenbloggar]

Wonderful! My professor forgot to mention that paired difference is useful when the parameters are independent. Homework suddenly turned very easy now, cheers mate!

[@piarodriguez6214]

hi. I just wanted to say that your videos are really good. Im failing stats for sciences at the moment. We are using the Navidi book for Engineers and scientists which is pretty much Chinese mandarin for me, but your videos are helping out a lot. Things make sense now. Thanks!

[@jbstatistics]

You are very welcome! I'm glad I could help.

[@jbstatistics]

I got that using software (R), but you could also find that the value is close to 0.01 using a t table.

[@SirGamestop]

Good vid dude. This beats reading the textbook

[@Pheshen]

If I measure every pair not once, say 7 times across the week. How then does the calculation work? Do I need to average the 7 numbers of each pair and calculate the usual way?

[@hikariwuff]

I'd like to reject my null hypothesis that I will pass this class

[@andrescheepers3223]

Hi JB, love your videos! I didnt quite catch your last point about how this sample isn't random and thus doesn't quite generalize to the larger population. Do you mean that a truly random sample would have sampled sets of twins randomly, capturing both normal and half-schizophrenic sets of twins?

[@jacquelineoliver9415]

your videos are amazing its helped me so much with my stats class thank you

[@jbstatistics]

You are very welcome! I'm glad to be of help!

[@niki-mendozacatalan5903]

So do we fail to reject the null hypothesis?

[@virtuousjoffrey8022]

My problem is identifying between dependent and independent populations and hence samples , can you help me out in identifying them without any problems?

[@stxroshan]

If sample size is large, do we still use the t test statistic? Or do we change over to the z test statistic?

[@Xerathful]

Don't we have to do affected-not affected when we calculate the difference?

[@jbstatistics]

The conclusions, interpretations, and all the rest are the same whatever way we take the difference, only the sign of the sample mean, test statistic, and endpoints of the interval change. So if we're simply trying to investigate the question at hand, then we can take the difference whichever way we like. Some people might want to take the difference as affected - not affected, thus having the difference represent some "effect of schizophrenia", but that's not necessary. For the purposes of this example, I found that the explanations are a little more awkward to discuss with that pesky negative sign around, so I went with what resulted in a positive mean difference.

[@Xerathful]

@@jbstatistics Thank you for so quick reply, yesterday , our teacher showed us as affected-no affected. :)

[@harmannd7270]

how did you get the p value to be 0.01? when i look on the z score chart 3.0= 9.987 (1-9.987)=0.001 isnt that the p value?

[@jbstatistics]

In this video I carry out a t test, and not a z test, so it wouldn't make sense to look up values in the standard normal table. The value I get in the video is from software, but one could look up a range of values in the t table.

[@winterfell14]

Thank you! Just one question, how did you get the p-value of 0.01? Thanks :D

[@hikariwuff]

There's this command in Rstudio (A statistics program) called pt, if you put in the following command: pt(3,14,lower.tail = FALSE) and then double that answer since it's a two-sided test, you get 0.01 if you round.

[@kodido00]

Thank you very much, very clear explanation, much appreciated !

[@1diana1995]

Why don't you use the formula with sigma to find standard deviations of differences

[@jbstatistics]

The primary reason is that we don't know the value of sigma (the population standard deviation). In this example we have sample data, and we have a sample standard deviation. This is typically the case in practice.

[@anhtrinh7935]

how did you find the standard deviation?

[@jbstatistics]

It's the regular sample standard deviation formula applied to the 15 differences.

[@anhtrinh7935]

i got it! thanks!

[@liamcasey5829]

great video, as always

[@jbstatistics]

Thanks!

[@johnxavier2226]

Wow Understood in just a minute !! Thanks :)

[@jbstatistics]

You are very welcome!

[@BasZz2119]

like the explaining, goodjob

[@jbstatistics]

Thanks!

[@hamedhosseini4938]

Nicely done sir :D

[@brentwalker173]

It seems like he is developing schizophrenia as the video progresses, nice helpful video though.

[@sachinhalajole6473]

thank you sir... because i will get more of interesting problems.. also how touse shortcut methods in that problems..once again thank you so much sir... I'm SACHIN HALAJOLE Rani Channamma university Belagavi .. Mcom student

[@jbstatistics]

You are very welcome! I'm very glad I can be of help to students around the world!

[@EthansTerrarium]

This helped a lot. Thanks :)

[@jbstatistics]

I'm glad to be of help!

[@Fl0pus]

SE(X) hehehehehe but seriously, very helpful once again, thank you

[@jbstatistics]

You are very welcome!

[@armanozcan7983]

was looking for this comment

[@davidsavage519]

That schizophrenia example is a bit morbid lol. I keep seeing morbid problems in statistics.

[@MalikOnYT]

You're amazing

[@jbstatistics]

Thanks!

[@drallisimo34]

cool!!!

[@jbstatistics]

Very, very cool :)

[@Rawrvenger1]

Thank you!