basic stat concept Flashcards
what is the purpose of base stat concepts?
- describe the difference between scales
- explain normal distribution and standard deviation
- differentiate the measure of central tendency
- explain validity and reliability
what are the types of measurement scales?
- nominal
- ordinal
- interval
- ratio
what is the nominal scale?
- qualitative measure.
- named category
- most basic of measurement scales
- only provides info about the difference.
pie chart where you can see what has happened/ your plan. YTD of finances for 12 months.
what is ordinal scale?
- qualitative measure.
- no indication of how much better something/ result is, just says its better.
Ex. medal podium. we know the first place person was better than the second but we don’t know by how much.
what is a interval scale?
- quantitative
- scores may be zero.
- tempeture can be measure below zero, so it is a interval scale.
what is a ratio scale?
- quantitative.
- there are no zero numbers involved.
- waist to hip ratio, blood pressure.
what are the measures of central tendency?
- mean (average)
- median (middle)
- mode (most frequent)
what is the mean in stats?
- the arithmetic average of the distribution of scores.
- sensitive to outliers. (only counts the majority)
- used with interval & ratio data
what is the median in stats?
- where 50% of the scores are ABOVE and 50% of scores are BELOW.
- when N is odd then the median is the middle score.
- when N is even then the median falls between the two middle scores.
what is mode in stats?
what is the mode of 2,4,7,5,9,7,0,1,7,
- the most frequent score in a distribution.
-7
how is variability measured?
- range
- standard deviation
how is range measured in variability?
- you take the high of X and subtract it from the low of X
(H-L=range)
why is variability important?
- it is important because you can collect more data and see what is actually happening and if the person is improving.
what is standard deviation?
- if the mean is 10 and SD is 2 (10+/- 2), where will majority of the data fall?
- provides information on the amount of variation or dispersion from the mean.
- tells us how close a set of data is.
- between 8-12
if the data is normally distributed then where should the SD score fall?
- 68%
what are correlations?
- numerical co-efficient that indicates the extent to which variables are related.
- r is between -1.00 & 1.00
what are 2 examples of correlation?
- Pearsons correlation
- intraclass correlation
what is the correlation of the fallowing?
- +1.00
- 1.00
0.00
+/- 0.5-0.7
+/- 0.7-0.8
+/- 0.8 to higher
- perfect positive correlation
- perfect negative correlation
- no correlation
- low correlation
- moderate correlation
- strong correlation
what is a perfect positive correlation?
when something else in/decreases then something also in/decreases at the same rate. they move together.
what is a perfect negative correlation?
- one variable increases while the other one decreases.
EX. the longer it takes me to run 1 mile (increase) the lower my VO2 max is (decrease)
what is Pearsons correlation?
- used to correlate two different variables.
- only two tests can be measured at the same time.
what is validity?
- validity refers to the accuracy of a measurement.
- r should be +/- 0.80 in order to be considered valid.
what is reliability?
- reliability refers to the consistency of how we measure.
- if we fallow the exact same procedure will we get the same results.
- r should = +/- 0.90 is considered to be reliable.
- can a test be valid if it is not reliable?
- can a test be reliable if it not valid?
- No, a test must be reliable in order for it to be valid. if you are not testing the a certain test the same way then your accuracy (valid) score does not matter.
- yes, because you are fallowing the repeatable procedure, but if it doesn’t measure the correct test then your not really accomplishing much.
