Statistics help!

[1908PharmD]

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Can someone pleeeaase help me out with this question?

......... EDited ......
My classmates and i keep wrecking our heads to do this. We can't find our professor anywhere. (Seriously)😕
Any help would be greatly appreciated .. thanks.

 

[vegasbaby]

1. [Replacement time (9) - Mean (8.1)]/Std. Dev. (1.4) = 0.64. Gives a z value of .2389. But that is for it falling within that distance from the mean. So if you want -above- that, you must subtract from .5. Gives a probability of 26.11%.


2. [25-24.2]/4.2 = 0.19. Gives a z value of 0.0753. Again, this is distance from mean, so we will subtract it from, in this case, the second distance from mean which is:
[32-24.2]/4.2 = 1.86. Gives z value of .4686. Probability is 39.33%.

I wish I could draw some bell curves on here. I find them very useful!

 

[1908PharmD]

thank you so much ! 😀

 

[1908PharmD]

Okay I showed this to my teacher and she said it is still wrong. Thanks for the advice anyway. Everyother way my classmates and I did these problems were wrong too! I think she solved it incorrectly if you ask me. And she is still not giving us the correct method to solve it or the correct answer. UGGGHHH !! annnnnd finals are next weeek!!!

I am so oooo frustrated right now. 😡

 

[vegasbaby]

Hmmm. Will you post the parameters again please? I am intrigued why this is incorrect...

 

[1908PharmD]

Everyone was complaining because nobody got it right, and finally she rechecked it and there was an error in HER calculations! 🙄

You were right! Thanks..


Oh .. BTW.. I just took my final yesterday and

I GOT a 90 BABY!!! Whoooooohoooo! The mean for the class was 71.6 for the final.

I am sooo glad that class is over!

 

[vegasbaby]

Awesome! Congrats! Nice score, quite above the mean, but what was the std. dev.? Just kidding!!