One Sample z-Test

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Category:

Education

Tags:

• z-test
• one sample z-test
• null hypothesis
• alternative hypothesis
• decision rule
• test statistic
• results
• conclusion

[rosebud040686]

Hi there.. these are very helpful thank you so much. I really am lost when you speak about alpha though. Which lecture do you deal with the concept of alpha? I have watched them all but could not find anything?

Thanks again.

[statslectures]

@rosebud040686

I don't think I have an in-depth lecture for Alpha just yet. I think I talked about it a fair bit in the Type I and Type II Errors video. Essentially, alpha is the probability of making a Type I error. Check out those videos, and if that doesn't help just send me a message and I'll be glad to answer any questions for you.

[thehammer401]

the part where you get the area for the tail/body... shouldn't you use the area for .95%? you used the value for 97.5%, but if you're taking the value for when there's 2.5 percent on each side...Sorry, I'm kind of confused.

[statslectures]

@thehammer401

Remember that there 5% is split into two tails that are each 2.5%. So, to find the value that is located at each of those tails, I use 97.5%, because 100 - 2.5 = 97.5. The z distribution is symmetrical, so the critical value is plus or minus 1.96. If I were to use 95%, I would be saying there are two 5% tails, which would be incorrect. Does that make sense? Let me know if that didn't help.

[onyeka112]

1.If a null hypothesis can be rejected at level alpha=0.03, what can u say when alpha=.05

2.what can u say when alpha =0.01

Dude this question has been bugging me all week ..i really will appreciate if u will be kind enough to explain this.

[statslectures]

@onyeka112

I had trouble saying what I wanted to in text, so I made a video for your question. Let me know if you have any more questions. You can access the newest video from my YouTube Channel.

[swaminathans1981]

@ statslectures: Very nicely explained. Thank you!

[huhuh01]

Thanks for this! :))

[mysoukouss]

You are an awesome statistics instructor. I like how you show the statistical tables, formulas on the screen, how you explain different concepts and follow logical steps with your calculations. Your examples are excellent. God bless you and please continue making statistics easy and sharing your knowledge with the trapped student community.

[rosebud040686]

Ah yes of course thanks! Sorry didn't see Type I and Type II errors there. That makes a lot more sense.

Thanks again for your lectures. I am a distance learner and would not know what to do if I only had my textbook. Really appreciate these.

[underpantsjihad]

If I had some of that medication, I wouldn't need to be watching this video

[emanweri]

Very clear and so useful, thank you very much!!!!