Σ symbol means the total sum. It is the Greek letter capital sigma.
fstands for frequency (count)
p stands for proportion, which is the same as f divided byΣ
Histograms:
bars in the chart have no space between them, unless we have any bins with a frequency of 0, then bars might be missing
Y-axis is used for frequency
X-axis is used for numerical data (meters, age, etc), and not categorical data (countries, colors, etc)
bin: one group of data, shown with a bar
bin width: the size on the x-axis for one group of data
skewed histogram does not have a normal distribution, where the highest frequencies are in the center and a graph representing the histogram is close to symmetrical.
Positively skewed histogram: Higher frequencies to the left
Negatively skewed histogram: Higher frequencies to the right
a frequency table holds the data for a histogram, like the blood type data in lesson 6
Bar charts:
relative frequency bars will add up to 100%, bars with overall percentages may not