Intro Descriptive Stats/Data Sum

Question 1

Measures of center and location

Answer 1

mean median mode weighted mean

Question 2

measures of variation

Answer 2

range IQR variance standard deviation

Question 3

negative of mean

Answer 3

affected by extreme outliers

Question 4

pth percentile in data array means

Answer 4

p% are less than or equal to this value

Question 5

quartiles do what to the data

Answer 5

split ranked data into 4 equal groups

Question 6

formula to find path percentile in ordered array

Answer 6

p/100 (n+1) = position

Question 7

disadvantages of range

Answer 7

ignores way in which data distributed

sensitive to outliers

Question 8

advantage of IQR over range

Answer 8

not sensitive to outliers, provides sense of typicality (range of middle 50% of values)

Question 9

variance

Answer 9

average of squared deviations of values form the mean

Question 10

sample variance:

Answer 10

sum of diffs between each observation and mean squared and divided by samples - 1

Question 11

difference in formula b/w sample variance and pop variance

Answer 11

population divide by N

Question 12

standard deviation shows

Answer 12

variation about the mean

Question 13

whiskers of box and whisker plots extend to

Answer 13

1.5 IQRs from 1st and 3rd queartile

Question 14

scaled data types

Answer 14

values assigned by measurement (potassium) or contain (number of kids)

Question 15

categorical data type

Answer 15

values assigned buy classification (blood type)

Question 16

nominal measurement

Answer 16

categorical; cannot be ordered

occupation, gender, eye color

Question 17

ordinal measurement

Answer 17

categorical; categories convey info about direction but intervals between categories don’t reflect same quantitative difference (small/med/large)

Question 18

interval

Answer 18

scaled; data on measurement scale with arbitrary zero point in which numerically equal intervals at diff locations on scale reflect quantitative differences
dont have natural zero point
can destroy zero when doing calculations
temp F

Question 19

ratio

Answer 19

scaled and continuous
data on measurement scale with true and absolute zero
numerically equal intervals at diff locations on scale reflect same quantitative difference (height, weight)