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Statistics help needed

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OK all you smarty pants...I'm taking Statistics graduate level and I have NO FREAKIN' clue what I'm doing. Anyone think you can help?

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Hot Mama
At least you know where you stand even if it is in a pile of shit.

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Statistically, my pants are no smarter than your pants. They are both inanimate objects, and therefore have no cognitive or teaching talents.

Did you hear the one about the constipated mathematician ?


Don
"When in doubt I whip it out,
I got me a rock-and-roll band.
It's a free-for-all."

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Statistically, my pants are no smarter than your pants. They are both inanimate objects, and therefore have no cognitive or teaching talents.

Did you hear the one about the constipated mathematician ?


Don




One and one finally made two?
lisa
WSCR 594
FB 1023
CBDB 9

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85% of all statistics are made up on the spot.



That's only true 73.8% of the time though.
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

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In other words....non of you are any more educated than I am.

Where is Bill when ya need him?



Why don'tcha just post the question you're needing help with?
"I may be a dirty pirate hooker...but I'm not about to go stand on the corner." iluvtofly
DPH -7, TDS 578, Muff 5153, SCR 14890
I'm an asshole, and I approve this message

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Here is the problem:

Think of a distribution of scores for which the mean is 65.5, the median is 64, the mode is 60, and n = 40. Suppose you later learn that one of the scores is in error. Instead of 70, the score should have been 90. What would be the value for the mean after changing the score of 70 to 90?

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Hot Mama
At least you know where you stand even if it is in a pile of shit.

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Here is the problem:

Think of a distribution of scores for which the mean is 65.5, the median is 64, the mode is 60, and n = 40. Suppose you later learn that one of the scores is in error. Instead of 70, the score should have been 90. What would be the value for the mean after changing the score of 70 to 90?



66

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OK that actually made sense. I knew it would increase but wasn't sure how to determine it and the formula kept showing it going down.

Thank you!

--
Hot Mama
At least you know where you stand even if it is in a pile of shit.

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Here is the problem:

Think of a distribution of scores for which the mean is 65.5, the median is 64, the mode is 60, and n = 40. Suppose you later learn that one of the scores is in error. Instead of 70, the score should have been 90. What would be the value for the mean after changing the score of 70 to 90?



66




agreed. now he'll probably want an explanation too... :P

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Elementary teachers do not think above the whole add, subtract, multiply, or divide stage. I'm having to wrap my head around this stuff.

Thanks for your help!

--
Hot Mama
At least you know where you stand even if it is in a pile of shit.

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OK that actually made sense. I knew it would increase but wasn't sure how to determine it and the formula kept showing it going down.

Thank you!



It all goes back to the definition of each of those values. The mean is the average: all values added together, then divided by the numbers in the set (n). You add 20 to the total because it's the difference of the incorrect value from the correct (higher) one. If you need the extra step, essentially once you get the sum of all the scores (65.5x40), you "take out" the incorrect value (-70) and replace it with the correct one (+90).

With the information given, you would not be able to find the new median.
See the upside, and always wear your parachute! -- Christopher Titus

Shut Up & Jump!

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OK that actually made sense. I knew it would increase but wasn't sure how to determine it and the formula kept showing it going down.

Thank you!



It all goes back to the definition of each of those values. The mean is the average: all values added together, then divided by the numbers in the set (n). You add 20 to the total because it's the difference of the incorrect value from the correct (higher) one. If you need the extra step, essentially once you get the sum of all the scores (65.5x40), you "take out" the incorrect value (-70) and replace it with the correct one (+90).

With the information given, you would not be able to find the new median.



Yes, but you would only have to know the position that the replaced "70" occupied in the sequence. The median will still be 64 unless a "70" was #21 in the sequence and it was the only "70" in the string. (since 64 is simply the average of the middle two numbers).

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OK that actually made sense. I knew it would increase but wasn't sure how to determine it and the formula kept showing it going down.

Thank you!



It all goes back to the definition of each of those values. The mean is the average: all values added together, then divided by the numbers in the set (n). You add 20 to the total because it's the difference of the incorrect value from the correct (higher) one. If you need the extra step, essentially once you get the sum of all the scores (65.5x40), you "take out" the incorrect value (-70) and replace it with the correct one (+90).

With the information given, you would not be able to find the new median.



Yes, but you would only have to know the position that the replaced "70" occupied in the sequence. The median will still be 64 unless a "70" was #21 in the sequence and it was the only "70" in the string. (since 64 is simply the average of the middle two numbers).



Ah yes, good point, since "n" is even.
See the upside, and always wear your parachute! -- Christopher Titus

Shut Up & Jump!

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