Answer :
Let's analyze the test scores provided: 18, 12, 18, 15, 15, 17, 18, 19, 20.
a) Calculate the mean.
The mean (average) is calculated by adding all the numbers together and then dividing by the count of numbers.
First, add all the scores:
[tex]18 + 12 + 18 + 15 + 15 + 17 + 18 + 19 + 20 = 152[/tex]
There are 9 scores in total. So, the mean is:
[tex]\text{Mean} = \frac{152}{9} \approx 16.89[/tex]
Therefore, the mean of the scores is approximately 16.89.
b) Find the median of the data.
The median is the middle number when all numbers are arranged in ascending order.
Arrange the scores: 12, 15, 15, 17, 18, 18, 18, 19, 20.
Since there are 9 numbers (an odd count), the median will be the fifth number:
Median = 18
c) Write down the mode.
The mode is the number that occurs most frequently.
From the arranged list: 12, 15, 15, 17, 18, 18, 18, 19, 20, the number 18 occurs most frequently (three times).
Thus, the mode is 18.
d) Determine the range.
The range is the difference between the highest and lowest scores.
Highest score = 20, Lowest score = 12.
[tex]\text{Range} = 20 - 12 = 8[/tex]
Hence, the range of the scores is 8.
