Statistics quiz (quantitative variables)

Finding frequency

4 steps:

• rank data least to greatest

• identify min and max

• choose # of classes (5-20) for K value

• compute to find class width

Class width equation Cw

Cw = (max-min)/k

Cumulative frequency

first CF = first class frequency

Last CF = # of elements

Cumulative relative frequency (CRF)

CRF = CF/Total

Cumulative Percent Frequency (CPF)

CPF = CRF x 100%

Two types of quantitative graphs

• Stem and Leaf display

• Histogram (bars touch)

Left skewed histogram

• Longer tail to left

• mean is similar to median

• skewness is negative (more left)

Right skewed histogram

• Longer tail to right

• mean is higher than median

• Skewness is positive (more right)

symmetrical histogram

• Tail is even on left and right

• mean = median

• skewness is 0