Term
| What is the Interquartile Range (Q) ? |
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Definition
| It's the difference between the 3rd and 1st quartile . So , Q3 - Q1 . It tries to give us a measure of the variability in the middle part of the data , and it improves on the range. Calculates the range of the middle fifty percent of the data. |
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Term
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Definition
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Term
| What eliminates high and low valued observations and calculates the range of the middle 50% of the data ? |
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Definition
| The Interquartile Range ( Q ) . |
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Term
| Only 25% of the observations are greater than .. ? |
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Definition
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Term
| What formula do you use to locate the position of the first quartile in terms of the data set ? |
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Definition
| .25n ..then whatever number you get , use that number to count to the spot of the first quartile. |
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Term
| What formula do you use to locate the position of the third quartile in terms of the data set ? |
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Definition
| .75n ... then the number you get from that , use that to count to get the number for Q3. |
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Term
| What are the steps for finding the Interquartile Range ? |
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Definition
1. order the scores from lowest to highest .
2. Find Q1 ( locate it using .25n )
3. Find Q3 ( locate it using .75n )
4. Then subract Q3 - Q1 :) |
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Term
| What does the Big Q stand for , and what does big R stand for? |
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Definition
| Big Q stands for Interquartile Range , and the Big R stands for Range . |
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Term
| Half of the data always falls between .. ? |
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Definition
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Term
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Definition
| the distance of any given raw score from its mean . |
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Term
| How do you find DEVIATION ? |
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Definition
| Just subtract the mean from any raw score . Sooo.. ( X- mean ) |
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Term
| The variable X with a bar ( __ ) above it stands for what ? |
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Definition
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Term
| The sum of actual deviations E ( x - mean ) is always what ?? |
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Definition
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Term
| How do we overcome the problem of the sum of the actual deviations always being zero ? |
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Definition
| We just square the actual deviations from the mean and then add them all together . So , E ( x- mean ) ^2 ...which is the sum of the squared deviations from the mean . |
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Term
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Definition
| the mean of the squared deviations. |
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Term
| The variable s^2 stands for what ? |
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Definition
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Term
| When dealing with variance/standardDeviation , to return to our original unit of measure , we do what ? |
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Definition
| Just take the square root of the variance , and it gives us the standard deviation . |
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Term
| What is the formula for the sum of the squared deviations from the mean ? |
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Definition
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Term
| The variable big N stands for what ? |
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Definition
| the total number of scores . |
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Term
| So , the sum of the squared deviations from the mean divided by big N will give you what varuiable , and what does that variable stand for ? |
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Definition
| It'll give you s^2 , and that gives you the variance, because s^2 stands for variance. |
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Term
| A big E in front of anything just means to .. ? |
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Definition
| The sum of all of those types of things. Like if you had a big E in froont of (a+b) , that would mean the sum of all your (a+b)'s . |
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Term
| The variable little "s" stands for what ? |
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Definition
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Term
| What do we use the standard deviatiov for ? |
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Definition
| to put the variance in the right perspective , because the variance has the numbers or whatever squared . |
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Term
| So how do we calculate the standard deviation ? |
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Definition
| Just taking the square root of the variance formula ! Basically undoing the square. And the variance formula is just the sum of the deviations squared divided by big N. |
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Term
| Why is the standard deviation more interpretable than the variance ? |
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Definition
| Because the standard deviation is in the correct unit of measurement. |
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Term
| The greater the variability around the mean of a distribution ...then , ? |
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Definition
| the larger the standard deviation . |
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Term
| So s=4.5 and s= 2.5 indicates what ?? |
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Definition
| That s=4.5 has greater variability than s = 2.5 . |
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Term
| In terms of variability , a narrow bell-shaped curve means what ? |
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Definition
| That it has scores clustered around the mean . |
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Term
| In terms of variability , a wider bell-shaped curve means what ? |
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Definition
| It has a greater spread around the mean . |
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Term
| Although two sets of data can have the same mean , they can still have different ...? |
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Definition
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Term
| s it possible for two sets of data to have the same mean , but different variation ? |
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Definition
| Because variation is dependent upon the spread of the data values from the mean , so yeah they may have the same mean , but different bell shaped curves depending on how far/close their values are from the mean . |
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Term
| The dotted line up the middle of a graph usually represents the what ?? |
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Definition
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Term
| Anytime a formula name has sample in front of it , you know that you are dealing with little what ? |
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Definition
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Term
| Population always call for big ___ , and sample always calls for little __ ? |
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Definition
| Population calls for big N , and sample calls for little N . |
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