Answer :
Answer:
Step-by-step explanation:
To calculate the mean mark for the test and then express it as a percentage, we can follow these steps:
Part (a): Calculate the Mean Mark
First, let's list the marks of the 15 students:
31,18,6,26,36,24,23,14,29,28,32,9,11,22,21
Next, we sum these marks and then divide by the number of students to find the mean.
Step 1: Calculate the sum of the marks
31+18+6+26+36+24+23+14+29+28+32+9+11+22+21
Let's calculate this sum:
31+18+6+26+36+24+23+14+29+28+32+9+11+22+21=330
Step 2: Divide the sum by the number of students (15)
Mean= 15÷330=22
So, the mean mark for the test is
22.
Part (b): Express the Mean Mark as a Percentage
To express the mean mark as a percentage of the total possible marks (which is 40), we use the following formula:
Percentage=(
Total Possible Marks÷
Mean Mark)×100
Substitute the mean mark (22) and the total possible marks (40):
Percentage=( 40÷22 )×100
Percentage=0.55×100
Percentage=55%
So, the mean mark expressed as a percentage is
55%.
