Statistics lesson 1 examined in the summer Introduction to statistics The mean Finding the mean from...
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Transcript of Statistics lesson 1 examined in the summer Introduction to statistics The mean Finding the mean from...
Statistics lesson 1 examined in the summer
Introduction to statisticsThe mean
Finding the mean from a frequency table
Introduction to statisticsThe following shows the test results for 10 students
A B C D E F G H I J
S1 6 4 9 8 8 5 7 8 9 9
M1 7 8 9 8 6 8 5 8 8 9
How can we compare the test results?
The mode is the most frequent value.The median is the middle number when the values are ordered.The mean is the total of the values divided by the number of values.The range is the largest - the smallest value
We could calculate some statistics for the test results.
Mode Median Mean Range
S1
M1
A B C D E F G H I J
S1 6 4 9 8 8 5 7 8 9 9
M1 7 8 9 8 6 8 5 8 8 9
Conclusions?
A set of data with 8 values has ∑x = 24Find the mean value
The mean of a sample of 25 observations is 6.4.The mean of a second sample of 30 observations is 7.2.Calculate the mean of all 55 observations
WorksheetDo the Ex B qs
Finding the mean from a frequency table
Answer: mean = 416/21=19.809..=19.8 to 3sf
x f
12 2
17 6
20 8
25 4
30 1
Now do Ex C qs 1-3
Find an estimate for the mean of this set of data x
frequency
2≤x<4 2 4≤x<6 3 6≤x<8 7 8≤x<10 4 10≤x<12 1
Grouped frequency table