3321 exam 1 Flashcards
mostly textbook questions
Our ability to draw meaningful conclusions based on a sample statistic depends, in part,
on the _____ of our sample.
variability
. When we are engaged in drawing conclusions about a population we are using inferential statistics. (T or F)
True
Which one of the descriptions below about statistics and parameters is correct?
A statistic summarizes the data in a sample, but a parameter summarizes the data in a population
What is the practical distinction between discrete and continuous variables?
Discrete variables take on only a few different values, but continuous variables
can take on any value between the lowest and highest score.
Interval vs ratio scale
Both: differences between values is meaningful, but ratio has a meaningful zero: celsius vs kelvin. For ratio can say “twice as big”
where does the tail point for a positive skew?
to the right (positive end)
where does the tail point for a negative skew?
to the left (negative end)
nominal
name things
ordinal
ranking
Which typical measure of variability produces scores in the same units as the measurements themselves?
standard deviation
Why do we divide by n-1 in calculating the variance or standard deviation as an estimate of the population value?
Because once one knows the mean and n-1 of the scores, one already knows all the scores & Because dividing by n produces a biased estimate
The endpoints of an interval are called _____.
the real upper (and lower) limits
When will the median and mean be equal
when the distribution is symmetrical
when will the mode, median, and mean be the same
when the distribution is symmetric & unimodal
When would you use median as opposed to mean to measure central tendency?
to minimize the effect of extreme scores- median is more robust
