Tutorial 17-Hypothesis Testing And Statistical Analysis Using Z test

[@vyasishan3800]

Thank you Krish for putting efforts to explain this concepts.

[@madhuchandra123]

Please complete the statistics playlist.

[@amartamboli6718]

Null Hypothesis = 5 Alternative Hypothesis = not equal to 5 Significance level = 2%,1-1% either side... Area under curve using positive z-score table = 1-0.01=0.99=2.33(As per Z-score positive table) Decision Boundary = +- 2.33 Z-score = -2.53 Since Z-test value is less than -2.33 i/e. it is in the negative rejection region , So we reject the null Hypothesis ..

[@salmanshaikh5851]

Bhai mere ko to abhi bhi palle nai pada Kaha se tune sikha batai gake?

[@hades840]

it is one tail test look there is underline on less

[@harshshukla980]

decision boundary 2.05

[@sarveshpandey9047]

2.33 kha se aya z table me to diya he nhi h

[@sohamgoswami5165]

​​@@hades840yes that's what i was thinking so it'll be only one tail on the left side so decision boundary to be found accordingly, which will be = 1-0.02 = 0.98 please check this tomorrow is my exam 🙏🏻

[@arpitasharma28]

Really appreciate your efforts to upload this video... great explanation sir:)

[@vishaltiwaribnt]

thanks for Uploading in Hindi.....its much more understaniding.....

[@syedmuhammadabdullahshah7367]

Best teacher of statistics I have ever known, smooth explanation is the key of your lecture, Lots of love from Pakistan ( Your neighbour) 💌

[@anuraaganath]

pmean = 5, std = 0.5, smean=4.8, n=40; null hypothesis = pmean = 5 alternate hypothesis = pmean < 5 C.I = 1-0.02 = 0.98 z = -2.52 where the decision boundry is -2.06 as per the z table. So, we failed to accept the null hypothesis and the warranty should be revised

[@alex-vq1yy]

can you explain how decision boundary = -2.06 how you calculated CI please explain

[@owaisahmad8336]

@@alex-vq1yy We check in the z-table and add the (column, row) beginning values for the cell where we have 0.98 => 2.0 + 0.6 = +-2.06 CI

[@strangeboy0012]

@@alex-vq1yy C.I. = 1 -- S.I. AND DISISION BOUNDRY = -2.27 ( BY THE Z TABLE -2.3+0.03 = -2.27)

[@ketanverma7839]

This is what i got too

[@prathameshsharma7425]

Bhai galat hai last doctor wale e.g may 1-0.025 kiya tha jaha c.i 95% tha so according to this yaha 1-0.001 hoga

[@mahalaxmiindapure8961]

I got decision boundary between -2.33 to +2.33, z-score= -2.529, We will reject the null hypothesis means workers believe is true.

[@sumitkoshti1171]

Yes

[@codecurrents]

Correct 👍

[@ketanverma7839]

Why do u do 2 tail test in this Cuz the worker believes it to be less than 5 So it should be 1 tail isnt ? M confused

[@memememe2476]

@@ketanverma7839 then in previous question why we do 2tail test cuz the doc belives it to be more than 168

[@4aryannaircoaj428]

@@memememe2476 the doctor believes it to be different. It was not mentioned that he believes it to be more than 168

[@harshwadiya-g5x]

it is actually a left tail test , although in 2tail test also we are rejecting the null hypothesis, but according to the concept we should apply left tail test only.

[@sketchytv1321]

بہت آسانی سے مشکل کنسپٹ سمجھایا ۔شکریہ

[@EjazUddin786]

Hanji bilkul

[@MH_POLITICSS]

Decision boundry= +-2.33 Z score = - 2.52 Conclusion - if z score is less than -2.33 or greater than -2.33 then we reject null hypothesis. So -2.52 >-2.33 we Reject null hypothesis..

[@ashishvinod2193]

since our entire area under the curve value is = 1 -0.98 = 0.02 since it's left tail test.. out z test value =-2.52 2.52

[@rajsinghtomar8090]

no confidence interval how i solve plz reply

[@ashishvinod2193]

@@rajsinghtomar8090 if confidence interval was not given then by default assume 98% confidence intervals

[@sumitkoshti1171]

@@rajsinghtomar8090 bhai significance value is given 2% which is equal to 0.02, and by using significance value you can find CI from the formula significance value = 1-CI, 0.02 = 1-CI, CI = 1-0.02 = 0.98 which is 98%

[@MohiniGiri_07]

This video is quite helpful for revision point of view

[@sandeepprasad1626]

All topics are well explained .Great Work

[@jerryvlog2326]

sample size 30 is not rule to select test, we can choose ttest for sample size above 30 also, but due to CL theorem more samples tends to normal distribution means ttest to Ztest

[@kashish8521]

Hey buddy! Could you please explain to me how to choose between the z-test and t-test. Thank you

[@Abijittdulalrabha]

Awesome explanation.. never gonna forget .. thank you

[@amriteshsingh6969]

awesome job krish

[@ashan3453]

the explanation is too good sir

[@manjeshtiwari7434]

Thank you for such an amazing lecture

[@KartikSharma12364]

My decision boundary is not getting correct ,can you help me

[@manjeshtiwari7434]

@@KartikSharma12364 what's issue?

[@manjeshtiwari7434]

@@KartikSharma12364 if accept area is 98 how can be reject 49 and 49, out of 100 98 is accept area so we have 1% reject area on both side u need to rewatch

[@KartikSharma12364]

@@manjeshtiwari7434 what's the correct answer of decision boundary and z test

[@KartikSharma12364]

​@@manjeshtiwari7434decision boundary=2.33

[@kritikasinghal2867]

Very helpful video sir

[@KartikSharma12364]

A chocolate company claims that their new recipe for dark chocolate bars increases the average cocoa content from the previous recipe. They conducted a study where they sampled 50 dark chocolate bars and found that the sample mean cocoa content is 85%. The population standard deviation of cocoa content is known to be 8%. Test the company's claim at a significance level of α = 0.05. Anyone solve

[@MuhammadIbrahim-ju1tp]

great krish respect so much value

[@salmanshaikh5851]

Continue Sir Continue me sahi time per aaya hu bcz mera abhi 15 ma tutorial chalra hai😂🤣

[@sauravjha1714]

Null Hypothesis = Mean = 5 Alternative Hypothesis = Mean not equal to 5 Significance level = 2%,1-1% either side... Area under curve using positive z-score table = 1-0.01=0.99=2.33(As per Z-score positive table) Decision Boundary = +- 2.33 Z-score = -2.52 Since Z-score falls in the negative rejection area...we reject the null Hypothesis!!!

[@rokhaiyasultana9728]

i got the sme ans!!

[@souravsinha18]

No it is not a 2 tailed test so alternative hypotheis should be mean less than 5 years

[@salmanshaikh5851]

Bhai mere ko to abhi bhi palle nai pada kaha se tune sikha pata gake?

[@sauravjha1714]

@@souravsinha18 check your answer... My answer is perfectly right!!

[@souravsinha18]

@@sauravjha1714 no bro I did this I am sure this is right why are u taking 1-1% on both sides when the worker says that the bulb lifetime will decrease you should take it on decreasing side and then calculate it

[@rohitrohit6883]

Sir, I am very thankful to you for this video.🙂😇

[@Vishal_19]

U = 5 sd = 0.50 n = 40 x bar = 4.8 so area = 1 - 0.02 = 0.98 z_value will be 2.06 (dission boundry) 4.8 - 5 ----------- 0.05 * root 40 = - 2.52 we reject the null hypotheses the worker was right

[@satishrajput1192]

I am also getting the same result.

[@HarshitSharma-df7kx]

sir what do we do when we do not have a 2 tail test condition ??

[@alphapoint389]

Sir how formulas are derived?

[@WardaQamar-t9r]

May Allah bless you 👏👏

[@akashshakya8740]

pls provide lecture notes

[@baishalibiswas7525]

Please complete full playlist

[@prashindu]

For a two-tailed test with a 98% confidence interval, you would use 0.01 (or 1%) for the purpose of arriving at the z-score. This is because the remaining 2% is split equally between the two tails of the distribution, leaving 1% in each tail. So, you’d look up the z-score that corresponds to an area of 0.99 in a standard normal distribution table. However, for a one-tailed test with a 98% confidence interval, you would use 0.02 (or 2%) to find the z-score. This is because the entire 2% is located in one tail of the distribution. So, you’d look up the z-score that corresponds to an area of 0.98 in a standard normal distribution table. When in doubt, it’s generally safer to use a two-tailed test. This is because a two-tailed test is more conservative and does not assume a direction of the effect.

[@Cricstory0108]

Sir konse video ha hypothesis check karne wali

[@kdasurrenderedsoul7613]

Hare Krishna 😊 Thank you so much for this vidoe 😊😊😊

[@shaitan779gaming9]

Hi Krish, is it standard that we should always go with Z-test when sample size is above 30?

[@KhooniDastakk]

You are amazing

[@235_TusharShastrakar]

Is This playlist enough to learn statistics for data analytics ?

[@Prashantchaudhary-kf1fb]

yes bro

[@zarmeenakhan899]

can you make a video on cohort and case control as well?

[@rishabhchauhan8612]

This topic is For Data Analytics or Data science ??

[@DuraidKhalid]

for decision boundry i use this : for 2% significane 1-1 on both sides 1/100=0.01 , 1-0.01=0.99 and in z table value of 0.99 is 2.33 means +2.33 on right and -2.33 on left pls tell me am i correct ?

[@rajatjuneja8367]

yes sir

[@machine_log]

for question 2 we reject null hypothesis and accept alternate hypothesis because z-test fall less than -0.1

[@MaryamAbid-p3j]

V nice Sir

[@cyberpunkgaming7971]

Can anybody teach me how to look into the z-table and match values , I can't seem to get it , thanks

[@hardikanandani7377]

Ho = average warranty is 5 years. H1= average warranty is not equal to 5 years. Alpha = 0.02(Here it's less than 5 years ,so it's one tailed.) Area under curve = 1-0.02 = 0.098 Decision boundry = +-2.06 Z-score = -2.52 So Ho is rejected. So, the worker was right I think. Bulb will malfunction in less than 5 years.

[@souravsinha18]

yes it is correct but decision boundary should be -2.06 not + - 2.06

[@hardikanandani7377]

Correct.

[@sumiturkude1395]

@@hardikanandani7377 how did you find decision boundary.?

[@shashi_kamal_chakraborty]

@@sumiturkude1395 It's 1 - alpha = 1 - 0.02 = 0.98. Now, z-table look up for 0.98. Which is found to be -2.06

[@KartikSharma12364]

A chocolate company claims that their new recipe for dark chocolate bars increases the average cocoa content from the previous recipe. They conducted a study where they sampled 50 dark chocolate bars and found that the sample mean cocoa content is 85%. The population standard deviation of cocoa content is known to be 8%. Test the company's claim at a significance level of α = 0.05. Solve this problem

[@RealCheese15]

Sir kal paper hai aur ye pura samajh hi nahi aa raha tha, thank you🙏

[@fehmeedaayoub6559]

Paired and unpaired ka concept????

[@zero_analyst]

Hello sir thank you for explaining You have mentioned in conclusion if z test is less than 1.96 or greater than 1.96 then we reject Null Hypothesis but as results came 2.31 which is greater than 1.96 so we should accept the Null Hypothesis. I am now confused can you please clarify thanks in advance

[@itshimanshucreation8076]

Bro unhone bola hai ki we accept to reject the H0 if z test is lessthen or greater then 1.96.

[@vedchaudhari6587]

if it lies in range of 1.96 and -1.96 then accept it else for anything either greater or smaller , reject it.

[@VeenaAjjodi]

taught better than my stats faculty

[@dishantsonawane8510]

Why do we consider sample size 30 for differentiating between Z test and T test. Why not some other number ? Why not 'x' percentage of the population ?

[@raufurrahim878]

30 data points should provide enough information to make a statistically sound conclusion about a population. This is known as the Law of Large Numbers, which states that the results become more accurate as the sample size increases. The 30 is a rule of thumb, for the overall case, this number was set by good statisticians.

[@urvashirai8441]

If std not given and sample size more thn 30,thn which test is to be used?

[@CrocksJam]

if population std mean not given then we use t-test directly

[@AmitSharma-oh5uw]

make more video correlation regression and probability in stats

[@heeralalchoudhary1587]

Fabulous sir ..can I contact personally

[@dhananjaykharat4812]

(Z Test = -2.53)H0 has been rejected as (Z test VAlue is not in C.I range/Decision Boundry) so worker believe is correct.

[@vaishhh_likhii]

Thankyou so muchh,such a nice explaination!! best video for Hypothesis testingg......🤌

[@Liku108]

Sir what about f test

[@wewesusui9528]

Sir anova test pr video banao baki ke saare test statistic 7 days live me hue he cover pr anova test nahi hua he

[@dilipgyawali1776]

if population standard deviation is given and sample size is less than 30, then Z test???please clarify.

[@robinsunuwar6852]

you should go with t test if the sample size will be less than 30 we have to perform t test its basic rule.

[@swapnil2881]

Sir please stat ki playlist continue rakho

[@hardsoul00]

Sir CHI SQUARE AND ANNOVA KA VIDEO Bna dein mera paper ha iska next month 10th november ko

[@rajarshiroy8794]

I have a doubt, From other definitions I think that If we have the population standard deviation we can directly move for z test since we are concerned about the sample size only when we are talking about the sample standard deviation as for n>30 sample and population SD are similar. So, I think the flowchart would be a little different. Can anybody clarify this doubt please??

[@harshitgupta6452]

Yes you are correct

[@rajasaad3450]

wait for course completion !

[@vishujaiswal6160]

next video pl. sir

[@shailendrayadav6937]

Here bulb manufacturers question is a one tail test question because , worker believe that bulb will malfunction in less than 5yrs . So Null hypothesis= H0 = 5yrs alternate hypothesis = H1

[@theentertainmentworld3310]

Do any one get the z test value?? I'm getting my z test value which is +0.037 and decision boundary values as +3.1 and -3.1 , So i have to accept the null hypothesis Do anyone get any answer??? Sir am i correct??

[@sumitkoshti1171]

Nope, Decision boundary is +-2.33 and Z test value is -2.53, As -2.53

[@muhammadansar3373]

According to my calculation HO is accepted

[@importantforlifeyasharora9042]

Actuall fanda ya to kisi ko pata nahi hai ya wo samjhane me inko takleef hai. Maths bhi theory ki tarah padha rahe hai😂

[@robotsj2775]

Worst tutorial for z test This should not take more than 7-8 mins. Pls don't go into so much detail. Instead you would have solved 4-5 problems in 25 min.

[@danielrichard7575]

"promo sm" 🤗

[@sandeepprasad1626]

All topics are well explained .Great Work

[@pr_ateek]

Please complete the statistics playlist