Example
When three out of ten lottery tickets contain a winning number,
determine the probability for drawing two consecutive winning
tickets. (Alternate method)
The probability of acquiring a winning ticket after drawing just once
2
Basic theory
The problem is solved by considering the second draw.
Probability of acquiring a winning ticket on the first draw
3
=
10
Probability of acquiring a winning ticket on the second draw
2
=
9
The required probability is calculated as follows.
3
2
1
×
=
10
9
15
Chapter 7
Number of winning tickets
Total number of tickets
Statistics
“Statistics” are a means to examine the regularity of accumulated data,
and make predictions about the future.
(1)Measure of central tendency of data
Through a “measure of central tendency of data,” the properties of all
data can be expressed via one numeric value. Values used as a measure of
central tendency of data are shown below.
Value
Explanation
Mean
The combined sum divided by the number of data sets. In general,
“mean” refers to “arithmetic mean.”
Median
The central value when data is arranged in either an ascending or
descending order. In cases where there is an even number of data
sets, the average of the two most central values is adopted.
Mode
The highest value related to the frequency of occurrence of data.
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