Chapter 2- Frequency Distributions Flashcards
Displaying data
What are frequency tables typically used for?
Frequency table are used for discrete variables and displays counts. proportions, and percentages. Visual depiction of data that shows how often each value occurred.
How do you calculate frequency?
Sum all of the frequency counts
How do you calculate proportion?
Divide the specific value by the total frequency
How do you calculate percentage?
Cannot exceed 100%. Percentages are typically the digits behind the decimal point.
What is the function of a grouped frequency table?
A grouped frequency table is used when data is continuous (scale) or can take on a range of values. One can create intervals to bin data.
How are bins created?
Bins are created by determining rage of data (smallest to largest values), determine appropriate interval size, then list interval and count frequencies
What are histograms used for?
Histograms are used for continuous (scale) data. The X-axis (across the bottom) are the values of variable (in intervals). The Y-axis (vertically) is for frequency or proportions
What is the difference between a bar graph and a histogram?
Bar graph provide scores for nominal data and categories do not need to be arranged in a particular order; histograms provide frequencies for scale data
What are frequency polygons used for?
Polygons are graphs where the x-axis represents midpoints of intervals and the y-axis represents frequencies. A dot is placed at the frequency for each value, then the dots are connected.
What is a normal distribution?
A normal distribution is a specific frequency distribution that is a bell-shaped, symmetric unimodal curve- 1 peak. It looks like a mountain.
What are skewed distributions?
Skewed distributions are distributions in which one of the tails of the distribution is pulled away from the center. The tail goes to the right or to the left.
What is a positively skewed distribution?
A positively skewed distribution is a
distribution where the tail of the distribution extends to the right–a positive direction also called the floor effect (prevents a variable from taking on values below a certain point).
What is a negatively skewed distribution?
A negatively skewed distribution is a distribution where the tail of the distribution extends to the left-a negative direction also called the ceiling effect (prevents a variable from taking on value above a certain point).
