Descriptive Statistics

percentile (P)

shows the value below which a certain percentage of numerical table falls

percentile (P)

relative standing of a score within a distribution

percentile (P)

used for ranking, indicating where a data point falls within a data set

percentile (P)

shows how much of dataset has a lower value

percentile (P)

used for comparing individual values to the rest of the data set and understand position

percentile rank

percentage of individual w/ scores at or below particular x value

percentile rank

"90th percentile" is a ???

raw score

"x" in "Px * N = no. of participant" means????

descriptive statistics

gives a description or an idea of the scores

measures of central tendency

gives a description or an idea of the scores IN RELATION to the tendency of scores in the center

measures of central tendency

statistical measure that attempts to determine a single value that is most typical/representative of the entire set

measures of central tendency

we're able to get the best representative value

mean, median, mode, sum

measures of central tendency < (4)

mean (M or x̄)

measures of central tendency:

always use this type if it's possible

mean (M or x̄)

measures of central tendency:

average

mean (M or x̄)

measures of central tendency:

most reliable bc its sensitive to the exact value

median (Mdn)

measures of central tendency:

middle score

median (Mdn)

measures of central tendency:

used for extreme scores, skewed distribution, open-ended distribution, undetermined values (EX: 5+)

median (Mdn)

measures of central tendency:

ordinal

mean (M or x̄)

measures of central tendency:

interval/ratio

mode (Mo)

measures of central tendency:

nominal

mode (Mo)

measures of central tendency:

used for discrete variables

mode (Mo)

measures of central tendency:

shows which variable is the most frequent

no mode

measures of central tendency:

this is said if ALL of the variables have the same frequency

sum (∑)

measures of central tendency:

this is the total

measures of dispersion/variability

shows the distance or how much the data varies

measures of dispersion/variability

measures how well a sample's score is to represent a population

measures of dispersion/variability

challenges the central tendency for being the best number to represent the entire set

measures of dispersion/variability

the lesser its value, the more reliable or consistent (BUT NOT ACCURATE) the representative score is

homogeneous sample

sample with low measure of dispersion or variability

measures of dispersion/variability

this can determine whether we can be sure of the results or not

measures of dispersion/variability

this can help with the conclusion, but isn't the conclusion itself

range, standard deviation, variance, interquartile range

measures of dispersion/variability < (4)

range

measures of dispersion/variability:

formula = xₘₐₓᵢₘᵤₘ - xₘᵢₙᵢₘᵤₘ

standard deviation

measures of dispersion/variability:

1) x - x̄ = distance from mean

2) ∑((distance)²)/N

range

measures of dispersion/variability:

NOMINAL = mode

standard deviation

measures of dispersion/variability:

INTERVAL/RATIO = mean

interquartile range (IQR)

measures of dispersion/variability:

ORDINAL = median

range

measures of dispersion/variability:

measures the spread of the extreme scores only

range

measures of dispersion/variability:

shows the difference between the highest & lowest score

range

measures of dispersion/variability:

not sensitive = unreliable

extreme scores

term for the highest & lowest scores

standard deviation

measures of dispersion/variability:

shows the standard/average distance from the mean

standard deviation

measures of dispersion/variability:

describes whether the scores are clustered or wide around the mean

variance

measures of dispersion/variability:

square of standard deviation

variance

measures of dispersion/variability:

usually used in inferential statistics

interquartile range (IQR)

measures of dispersion/variability:

statistical difference between the 3rd quartile (Q3) and 1st quartile (Q1)

interquartile range (IQR)

measures of dispersion/variability:

formula = Q3 - Q1 or P75-P25

interquartile range (IQR)

measures of dispersion/variability:

encapsulates 50% of data which provides insight to the spread

P75

Q3 = percentile?

P25

Q1 = percentile?

descriptive statistics

its job is to simplify the organization and presentation of data