Add'l Statistics (7) Flashcards
Range…
Cannot be negative. Can only equal 0 if one term in set or all terms are same
St Dev
How closely terms in set are spread around its mean. Can’t be negtative and is only 0 if range is 0.
St Dev, multiplying each term in a sequence…
SD will increase
SD, divide each term in a sequence…
SD will decrease
SD, evenly add a # to each term in a sequence…
SD will stay the same
Greatest increase in a SD comes from…
Adding a # farthest from current mean
Role that the number of terms plays…
Set of consecutive integers sounds like it should have a smaller SD than a set of consecutive multiples of 100. But a million consec integers and only two multiples of 100, consec integers stray much farther from mean.
Adding a new value to a set will never…
Decrease the range.
When multiplying in a SD problem, multiply by…
Absolute value
Zero is neither…
Positive or negative.
If there is a SD to begin with…
You know that all volumes/levels/numbers cannot be the same from the start
If a question ever asks for “the mode”, that means there can only be…
One mode
Dividing by a number with an abs value less than one…
increases the value (this is essentially multiplying)
Mult by a number with abs value less than one…
decreases the value (essentially dividing)
Changing sign of all elements or multiplying by -1…
No effect on SD
