Hyp testing #3: Testing for μ when σ is unknown

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Example question:

An online fashion store called Showdonkey advertises that its average delivery time is less than six hours for local deliveries. A random sample of the amount of time taken to deliver packages to an address in Stanmore produced the following delivery times (rounded to the nearest hour):

7 3 4 6 10 5 6 4 3 8

Is there sufficient evidence to support Showdonkey's advertisement, at the 5% level of significance?

VIDEO LINKS TO COME!

zedstatistics

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My professor actually spent 3 hours to teach me about your hypothesis testing #1, 2, 3, 4 but I swear I can't even understand a thing.
Thanks to your videos, they taught me everything in like half an hour and literally saved me from my final exam.

sarahnguyen

"VIDEO LINKS TO COME!" I assume they'll be here any minute now. XP

Alresu

i cant believe i just saw his channel get 200k Subs, Im proud of you Justin

Mano-kc

"VIDEO LINKS TO COME!"

They never came...

MDMAx

Question: Step 4 says not to reject H0 hypothesis as t and p > 5% significance.
But Step 5 says we don't have necessary evidence that delivery times is less than 6 hours.

I thought step 4 creates necessary evidence that delivery time is less than 6 hours. Isn't it?

ramhariharan

Thanks so much for making these series, made a daunting topic so much less intimidating. Do you have videos on two sample independent/dependent testing?

JESSTHECAR

Isn't Null Hypothesis supposed to say Mu is bigger or equals to 6? If the alternative Hypothesis is saying Mu is less than 6 then i think the other one should say Mu is bigger is equals to 6!

awindaphilip

Thank u so much ❤, my final exam is tomorrow and I wasn't understand these things. You help me a lot, with your simplicity of explaining.

tuqaaldeiryah

Hii Very nice video, Thanks for making it :)

GamerAvi

5:34, its supposed to be 's' and not sigma when writing the formula. Though doesn't matter since it has been solved correctly

adarshtiwari

Hi Zed, amazing video! Thanks! One quick question - SD of sample uses (n-1) but why sample mean is always divided by n (not (n-1)

nancy

I still did not understand how we know population variance is known or unknown...plz explain again

farwashahid

How did you get the -1.833, because I can't find it on the t-distribution table?

studyingwhileinyourprime

is there a rule of thumb of sample size for normal approximation

lowqchannel

Hi sir plz can yiu tell me in this question which test will be used.
Three items have following values 12, 32, 21. Doea the mean of three values differ significantly with the population mean is 56 with level of significance 0.05

randomlymade