Question

suppose a class obtained the following test scores.
score frequency
90 2
80 5
70 10
60 6
50 4
40 2
30 2
0 5
what is the mean?

Explanation:

Step1: Calculate total score

To find the total score, we multiply each score by its frequency and sum the results.
For score 90: \(90\times2 = 180\)
For score 80: \(80\times5 = 400\)
For score 70: \(70\times10 = 700\)
For score 60: \(60\times6 = 360\)
For score 50: \(50\times4 = 200\)
For score 40: \(40\times2 = 80\)
For score 30: \(30\times2 = 60\)
For score 0: \(0\times5 = 0\)
Now sum these products: \(180 + 400+700 + 360+200 + 80+60+0=1980\)

Step2: Calculate total number of students

To find the total number of students, we sum the frequencies.
\(2 + 5+10 + 6+4 + 2+2+5 = 36\)

Step3: Calculate the mean

The mean is the total score divided by the total number of students.
Mean \(=\frac{1980}{36}= 55\)

Answer:

The mean of the test scores is \(\boldsymbol{55}\)