1. Section Ii: statistics
by moi (Jessica)

2. Questions… yay
1. Which of the following is a box and whisker plot?

3. What is the mode of the following set of numbers?
1, 2, 2, 2, 2, 3, 4, 5, 5

4. Letter B
Mode: 2

5. Probability or statistics?
While probability describes the odds that an event will occur, statistics describe numerical data from samples of a population.
For example, if I were to roll a die, the odds I’d roll a certain number relate to probability. But if I rolled a die a certain number of times and recorded what I got, then information about the group of numbers I got would relate to statistics

6. Measures of central tendency
Mean: average of all numbers in a set [add all numbers together and divide by number of amounts added]
Example: 1,2,3,4,5 added together equals /5=3
Median: the number in the middle of a set ordered from least to greatest
Example: 3,7,1,6,4  1,3,4,6,7
Example 2: 8,5,2,3  2,3,5,8  median= 3+5 divided by 2 (find the mean)
Mode: number that appears most often in a set of numbers. There can be no, one, or more than one mode.
Example: 1,1,3,4,4,4,5,6,6 the mode would be 4

7. Organizing and displaying data
Range: difference b/w highest and lowest number of a set
Example: 2,3,3,4,7 the range would be 7-2=5
Outlier: a value in a set that is much smaller or larger than the other numbers. It can significantly change the data and/or inflate/deflate the mean.
Example: 2,4,5,6,6,8,27  the 27 is a lot larger then the other numbers as it is in the double digits whereas the others are single digits

8. Stem and leaf plot
A simple diagram that lists all the numbers in a set by separating the tens value into a “stem” column and ones digits into a “leaf” column
The first number in the stem column is the lowest number’s tens place value. All whole numbers are listed between this number and that of the largest number’s tens place value in this column.
In the leaves column, for every number in the set there is a corresponding number that is the ones place value of each. If a number is repeated then the same number would be repeated. If no number falls under a certain stem column section then that row is blank. This helps organize large numbers in a set.

9. Box and whisker plot
A graph that organizes data based on range and quartiles.

10. Bar graph
Used to compare frequencies or occurrences in characteristics of data
Amounts… in bars… measured by height on side.

11. Scatterplots
Used to show the relationship, or correlation between two sets of data. They have points plotted on a graph with the first set of data on the horizontal axis as the independent variable and the second on the vertical axis as the dependent variable. Hey can have a positive correlation, a negative correlation, or no correlation.

12. Scatter plot stuff
Line of best fit: helps show relationship between two variables in the graph. It is drawn so that there is an equal number of points above and below the line and helps show whether the scatter plot has a positive or negative correlation
If there is no correlation then the line of best fit can’t be drawn.
The line of best fit shows a positive correlation if going from left to right upward and a negative one if it goes from left to right downwards

13. Sequences
Arithmetic sequence: a sequence in which the difference between any pair of successive terms is the same
Example: 4, 7, 10, 13, 16, 19  the difference any number and the previous one is 3 (7-4=3) (10-7=3) , so the next number in the sequence would be 19+3, which is 21
Geometric Sequence: a sequence in which the quotient of any pair of successive terms is the same
Example: 2, 4, 8, 16, 32  the quotient of any two successive term is 2 (4/2=2) (32/16=2) , so the next number in the sequence would be 64

14. More questions
1. The following sequence is an arithmetic sequence: 3, 6, 12, 24, 48
A. True
B. False
C. Can’t tell
2. The ______ is the difference between the lower and upper quartile.
A. The inter median range
B. The quartile range
C. The inter range mode
D. The interquartile range