AP Stats Unit 1

Unit Vocab

Quantitative - data that is numerical data.

Categorical - data that does not have an inherent order.

Mean - the average of the data set (Sum of all data divided by the number of all data).

Median - The exact middle of the data set (n+1)/2.

Range - Where all of the data values lie (Biggest - Smallest).

Quartile 1 (Q1) - The median of the bottom 50% of data.

Quartile 3 (Q3) -  The median of the top 50% of data.

Tables and Graphs:

Frequency Table

  • Has individuals, a tally, frequency, and relative frequency.

Two Way Table:

  • Describes two categorical variables.

Side by Side Bar Graph:

  • Used to easily compare 2 sets of data

Segmented Bar Graph:

  • Bars always go to 100%

  • Should not be colored in

  • No is shaded whilst Yes is left blank

Dot Plot:

  • Dots on a number line

  • Helps with scale but loses the exact numbers

Stem Plot:

  • Has a “stem” with “leafs”

  • compact but isn’t good with large data sets (congested)

Histogram:

  • Bar graph with intervals instead of exact data points

  • Great for large data sets but loses individual data points

Five Number Summary:

  • Consists of the minimum, Q1, Median, Q3, Maximum

Box Plots:

  • Used to show the 5 number summary and outliers

  • Box and whiskers

Notes

  • A misleading graphic has either no labels or scale, bad scale, and might use picture.

Describing an Association

  • Make a claim

  • Support that claim with data

  • Include context

Standard Deviation:

  • Best used when the set is symmetrical and has no outliers

IQR (Interquartile Range)

  • Q3 - Q1

  • Best used when the set includes outliers or is skewed

Resistances:

  • Median is resistant to skew and outliers

  • Mean is not resistant to skew and outliers

How Skew affects the median and the mean:

  • When right skewed the mean is greater than the median

  • When left skewed the mean is less than the median

  • When symmetric the mean is equal to the median

Determining Outliers:

  • Upper Limit - Q3 +1.5(IQR)

  • Lower Limit - Q1 -1.5(IQR)

CSOCS:

Context - What variable is being mesured

Shape. - Directional skews, symmetric, modes

Outliers - unusual points

Center - Mean, median, general center

Spread - Range, IQR, SD