UNIT 6 - STATISTICS
PARENT LETTERS
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OVERVIEW
In this unit, students will:
- Analyze data from many different sources such as organized lists, box-plots, bar graphs, histograms and dot plots.
- Understand that responses to statistical questions may vary.
- Understand that data can be described by a single number.
- Determine quantitative measures of center (median and/or mean).
- Determine quantitative measures of variability (interquartile range and range).
VOCABULARY
- Distribution – The arrangement of values that show the spread of the data.
- Dot Plot – A statistical chart consisting of data points on a number line, typically using circles.
- Frequency- the number of times an item, number, or event occurs in a set of data
- Grouped Frequency Table- The organization of raw data in table form with classes and frequencies
- Histogram- a way of displaying numeric data using horizontal or vertical bars so that the height or length of the bars indicates frequency
- Numerical Data- Consists of numbers only. Numerical data can be any rational numbers.
- Outlier- An outlier is an observation that is numerically distant from the rest of the data.
- Skewed Data –When a set of data is not symmetrical it can skewed, meaning it tends to have a long tail on the left or right side.
- Statistical Questions - A statistical question is one for which you don't expect to get a single answer. Instead, you expect to get a variety of different answers, and you are interested in the distribution and tendency of those answers. For example, "How tall are you?" is not a statistical question, however "How tall are the students in your school?" is a statistical question.
- Box and Whisker Plot- A diagram that summarizes data using the median, the upper and lowers quartiles, and the extreme values (minimum and maximum). Box and whisker plots are also known as box plots. It is constructed from the five-number summary of the data: Minimum, Q1 (lower quartile), Q2 (median), Q3 (upper quartile), Maximum.
- Inter-Quartile Range (IQR)- The difference between the first and third quartiles. (Note that the first quartile and third quartiles are sometimes called upper and lower quartiles.)
- Maximum value- The largest value in a set of data.
- Mean- The “average” or “fair share” value for the data. The mean is also the balance point of the corresponding data distribution.
- Measures of Center- The mean and the median are both ways to measure the center for a set of data.
- Measures of Spread- The range and the interquartile range are both common ways to measure the spread for a set of data.
- Median- The value for which half the numbers are larger and half are smaller. If there are two middle numbers, the median is the arithmetic mean of the two middle numbers. Note: The median is a good choice to represent the center of a distribution when the distribution is skewed or outliers are present.
- Minimum value- The smallest value in a set of data.
- Range- A measure of spread for a set of data. To find the range, subtract the smallest value from the largest value in a set of data.
- Variability – Describes how spread out or closely clustered a set of data is. Variability includes range and interquartile range.