Hypothesis Testing: One-tailed t test for mean

[@lagiordina4513]

i got an exam in 11 hours and this guy is a bloody genius. he makes it all so easy. thanks man, youre the best

[@Anonymous-yb7qu]

Are you writing the same exam as I am?😅

[@wiws6834]

A year later same situation

[@TorosFilmz]

I never get tired of learning statistics from your tutorials.❤

[@ifargantech]

I have an exam by tomorrow morning and you cleared up all my doubts. Thank you!

[@stevenhughes7380]

You are extremely good at explaining things in a way that makes sense! Thank you!

[@sihamsebouai8070]

Your clear voice and easy explanation made me obsessed with this channel

[@savagearmy4972]

How Can I thank you enough? You deserve A LOT OF LOVE ❤️ RESPECT FROM MY HEART

[@Quigglessish]

you are an actual life safer Mr. Emmanuel. Great videos.

[@Da-tu4oq]

I’m here before my exam and there’s only 12 hours left, thank that’s really help me

[@nickterrencegantalao589]

1:46 may I ask why the standard deviation isnt 4.8? its labeled 4.8 in the example problem but you substituted 4.6 for it

[@joshemman]

It was a typo; it should be 4.8. s = 4.8 was used to obtain -2.165 however.

[@orangegrass1]

the best video to explain the t-test!

[@ahmednaveed8256]

i was very confused about this topic got a final exam in about 12 hours Finally it makes sense Thanks alot

[@joshemman]

You're welcome. Hope your exam went well.

[@pixii5654]

Thank you I was very confused one the one sided thing for when to reject it, but the visualization with the tails graph helps sooo much

[@Thana1549h]

Everything looks so easy when I watched this video. Thank you so oooooooooo much.

[@LASTMINBOOST-xr7lb]

thank you sir, great explanation and presentation, very minute details are also explained well.

[@joshemman]

So nice of you.

[@felixlizwe1945]

Amazing easy to understand lecture. Very informative...

[@kimberly3194]

you are very very good thank u! my test is in 8 hrs I think I'll be saving me!

[@richardfader3021]

Standard deviation was 4.8 but on calculation you used 4.6, was it a mistake or there is a logic behind it?

[@aparna603]

Tysm sir for clearing the concepts

[@joshemman]

Always welcome

[@PrinceAdom]

at 4:46, why are we using a sample standard deviation of 4.6 when 4.8 was given in the problem? using the original value of 4.8 gives a t -score of -2.259 which is greater than the t-score of -2.479, It still leads to failure to reject the null hypothesis anyway

[@joshemman]

t is -2.165, using s=4.8.

[@PrinceAdom]

@@joshemman thank you i guess a mistake then

[@lizaminasyan9255]

U r the best❤️ I am so happy that I found ur channel

[@mehuldeshpande2953]

Very well explained sir.Sincere thanks

[@joshemman]

Glad to hear, Mehul. Thanks,

[@shakshineha]

when this is easy, but your prof sets the paper so tough, that understanding the question becomes a task

[@esthernyarko2335]

Please with this example given,how I’m I to know that it is a left tailed test ?

[@joshemman]

The keyword here is "below". Left-tailed test have words like "less, decreased, ...." Regiht tailed tests have "above, more, increased,..."

[@lovemath101]

Thanks so much, clear precise explanation!

[@pabodaweligamapalliyagurug9353]

Very useful.Thank you so much❤❤❤.

[@tchekdenis-ki3lo]

Thanks I get to solve my problems of maths statistics with your tutorial very easily. Please can you do for Kendall's rank correlations detailly.? I have problems there on how to get S

[@tsilavotahina]

you deserve subscribe. I'd learn with book but with you ,it's shorter and clear😁👏

[@favouronwuchekwa]

how did you get the 4.6 when the standard deviation was not given ?

[@benhanock3641]

s represents standard deviation, which was given in the first sentence, it is 4.8 (he made a mistake saying its 4.6)

[@CaribbeanMathGem]

You're brilliant!

[@phakyou]

Why didn't we see degree of freedom in previous lesson (two tailed test) but do in this one?

[@joshemman]

The Z-distribution does not use degrees of freedom.

[@alaaazouzi9121]

You helped me a lot thank u so much ❤ may allah help you 🥰😍

[@joshemman]

You're welcome! 🙏

[@albadi1]

Thanks Mr your tutorial is clear.

[@Kaylyn255]

2:23 you mixed up the standard deviation. Its 4.8 not 4.6. Other than that this video helped me a lot

[@wissalms2820]

I have hypothesis test for mean20 , should I solve this problem like the way we solve mean=20 vs mean>20

[@joshemman]

Yes. It's the same way. We just write the null differently.

[@dangkhoado7428]

thank you, this help me a lot

[@mmrida_]

thank you very much 💖💖💖

[@joshemman]

You're welcome.

[@ThozamileMadonda]

I think there was a mix up with -2.165 and -2.479. Why is -2.479 the cut off value and not -2.165?

[@joshemman]

The critical value, ( t = -2.479 ), separated the rejection region (shaded blue) from the non-rejection region. The goal is to determine whether the test statistic, ( t = -2.165 ), falls within the rejection region. If you calculate the area beyond the test statistic ( t = -2.165 ), you obtain the p-value.

[@MrQaydi]

It says the sample standard deviation is 4.8 but in the formula you wrote 4.6

[@joshemman]

You're right. It was a typo.

[@maxmacfarlane9890]

no worries Joshua! Very informative video. You've helped me so much.

[@samirahaddaoui5522]

aren´t we supposed to use the Z- test as we have a known variance /Standard deviation? Normally we use the t-test when the variance is not given.

[@joshemman]

We use Z when we know the population SD. What we have here is sample SD.

[@josephmsimango6069]

Thank You Chief

[@opikidi]

isn't the standard deviation 4.8 instead of 4.6

[@jalilnazarli13]

thanks a lot for helping out!

[@arbogastkanyinga9422]

shoutout to your videos, its that GOOD. too Good to be free

[@yenyenmainar4916]

how do we know that is left tailed or right tailed?

[@joshemman]

Look for (right-tail) indicators like "increase", "more than", and "above". The left-tailed counterparts will be "decrease", "less-than", and "below".

[@shadyalfons9302]

I have a Q sir Why don't we divide alpha on 2 in this example? 🤔

[@joshemman]

This is a one-tailed test so you do not need to divide alpha by 2. You only divide alpha by 2 in 2-tailed tests.

[@shadyalfons9302]

@@joshemman thanks sir you are the most talented genius teacher i have ever seen ❤️🌷

[@samkab677]

how to write the Hypothesized Mean Difference as in example in excel solver ???? should it be zero ??? can it be other than zero in other cases?? if yes can you provide an example ???

[@catpaul1680]

I wonder why we don't set H0 as µ

[@joshemman]

Ho must contain equality.

[@savagearmy4972]

HUGE HELP FOR ME

[@vencintanthonygimo]

I wonder why the null hypothesis is greater than or equal to 24. What if I used Ho: u=24?

[@joshemman]

I will suggest you follow the convention used in your text/course.

[@vencintanthonygimo]

@@joshemman thanks

[@sayyadinthiyaz890]

What is the z value

[@ankushbhawal4428]

Thank you so much

[@indumini4990]

Why did we use 0.01 and not 0.005? (alpha/2)

[@joshemman]

We used 0.01 here because this is a one-tailed test so we do not need to divide alpha by 2. If it were a 2-tailed test, we will use alpha/2.

[@sinaabedini7487]

Bless you

[@hhykk]

S and Theta are both for Standard deviation isnt? S is 4.8=Theta is 4.8 ?

[@kashishsharma1826]

yea and they wrote the wrong value of standard deviation lol, they literally explained one question that too wrong

[@wakanakameza2011]

This is good but you said standard deviation is 4.6 or 4.8 how did you do it or it’s a mistake 😢

[@joshemman]

Yes, the 4.6 is a typo (at 1:44). It should be 4.8.

[@hamzasenhaji4154]

normally is 4.8 / squar root 27 not 4.6 there is a mistake

[@veranyambura3194]

I was looking for thuis comment A.

[@nayanchakraborty8725]

in question "s"= 4.8 but you kept 4.6 in equation, why ?

[@joshemman]

4.6 was a mistake, sorry. 4.8 was used to do the calculation.

[@bintalshati]

hi, how we know where is the claim ?

[@joshemman]

The claim is usually written somewhere as part of the problem statement. For example, if you’re testing if a prof states that the average score is less than 70, then the claim is that “the average score is less than 70%”

[@hydershaikh83]

last year 50% of MNM employees where female.it is believed there is a reduction in the percentage.random sample is 400, 180 where female.use 5% significant level.can u solve this one i am confused about N,S,X value what to take..i cant understand % sums

[@joshemman]

This is a proportion problem with p^=180/400. H0: p>=0.5 H1:p

[@hydershaikh83]

Joshua Emmanuel what will be the formula for this one.i have tomorrow stat exam and this sum conduct 10 marks so plz help me with the formula.Thanks a lot for replying.ur lectures are awesome.

[@joshemman]

Use the z formula for testing a population proportion.

[@hydershaikh83]

Joshua Emmanuel thanks again..

[@settiemaidamutia5580]

Why is -2.165 not less than -2.479?

[@joshemman]

because larger negative values are smaller in value.

[@mandeepbaluja5401]

Love you bro

[@MuhammadYousaf-hq2zh]

thankyou sir,

[@MrQaydi]

How do you solve this problem: H0 µ >= 3 H1 µ < 3 Sample size = 23762 Missing = 172 Sample mean = 3.14 Sample variance = 0.51 Sample std. dev. = 0.72 Sample std. err. = 0.00 T value = 676.55 This T value is calculated by a software. Is there enough evidence to reject the null hypothesis?

[@umemashoaib4782]

Lovely

[@clocktowerhill8760]

Outstanding!

[@aaronroman7384]

S=4,8 but you wrote 4,6 in the question

[@joshemman]

Yes. At 1:45, it was a typo. This is the first time I'm seeing it. Thanks for pointing it out.

[@mathstendstoinfinity9002]

Sd is 4.8.,,why you use 4.6

[@joshemman]

It's a typo. The result was calculated using 4.8.

[@nakhlarafi5118]

Can you please explain why you used t test here?

[@catpaul1680]

standard deviation of population is unknown, sample size

[@Dist0001]

Thank you for video. you help me more than paid professor. @John Trapasso if you see this SMH

[@joseignacionoarbesulayman915]

eres la ostia

[@richardfader3021]

Standard deviation was 4.8 but on calculation you used 4.6, was it a mistake or there is a logic behind it?

[@joshemman]

At 1:44, you're right. The 4.6 was a typo. The answer (-2.165) was computed based on 4.8.

[@richardfader3021]

@@joshemman thank you sir