little stats things to remember

percentile

p*n/100 where p is the __th percentile and n is the number of data points given

how do you assemble a box and whisker plot?

1) make sure the data is going from smallest to largest

2) calculate extreme and moderate fences

3) draw a line that includes the x values given in the problems as well as all of the fences you calculated

4) draw box - edges of the box are q1 and q3, line in the middle of the box is the median (label all three)

5) draw whiskers - whiskers go to the smallest and largest in the list AS LONG as it isn’t an outlier. if there is an outlier, you draw the whisker to the next valid value. outliers are marked with a dot

6) draw the inner and outer fences you calculated with dotted lines

DONE!

how do you assemble a leaf plot?

1) arrange data points in ascending order

2)

how do you assemble a histogram?

1) calculate classes —> 1+3.3log(n) (round up)

2) calculate class width —> range/classes (round up)

3) make frequency table

4) label histogram axes (x-axis - classes interpreted by the question, y-axis - percentage)

^^ all info for the histogram is obtained by the frequency table

5) bars of the graph are the class width

DONE!

empirical formula

68% = 1 standard deviation

95% = 2 standard deviations

99.7% = 3 standard deviations

population

complete set of individuals or events relevant to a research question

sample

a subset of the population selected for measurement when studying the entire population is impractical

y-bar

∑y/n that same way x-bar = ∑x/n

prediction

estimate

discrete

countable data

ex: number of books, dice outcomes, number of students

continuous

any value in a given range, measurable and can include decimals and fractions

ex: weight, age

class equation for histogram

1 + 3.3log(n)

what’s in a frequency table?

1) classes, 2) frequency (just how many of the data points within the class range), 3) relative frequency (freq/total number of data points), 4) percentage (rel freq * 100)

expected count

(row total)(column total) / overall total

degrees of freedom

(# of rows - 1)(# of columns - 1) not including totals