Mrs. Gifford's class consists of 15 girls and 25 boys.
On the first test the mean of the girls’ scores was 80 and the mean of the boy’s scores was 70. What was the class mean? (Remember the class mean is not just averaging the two means)
On the second test, the class mean was 80 and the mean girl’s scores was 75. What was the mean of the boy’s scores?
Whats the second tests answer
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i need the answer to the second part they did not show me that
To find the class mean on the first test, we need to find the weighted average of the girls' scores and the boys' scores, where the weights are the number of girls and boys respectively.
First, we calculate the total score of the girls by multiplying the mean score by the number of girls: 80 * 15 = 1200.
Next, we calculate the total score of the boys by multiplying the mean score by the number of boys: 70 * 25 = 1750.
To find the class mean, we sum up the total scores of the girls and boys and divide it by the total number of students in the class: (1200 + 1750) / (15 + 25) = 2950 / 40 = 73.75.
Therefore, the class mean on the first test is 73.75.
Now, let's move on to the second test. We know that the class mean on the second test is 80 and the mean of the girls' scores is 75.
To find the total score of the girls on the second test, we multiply the mean score by the number of girls: 75 * 15 = 1125.
To find the total score of the boys on the second test, we subtract the total score of the girls from the total class score on the second test: 80 * (15 + 25) - 1125 = 4000 - 1125 = 2875.
To find the mean of the boy's scores on the second test, we divide the total score of the boys by the number of boys: 2875 / 25 = 115.
Therefore, the mean of the boy's scores on the second test is 115.