Answer:
144
Step-by-step explanation:
Let's say the test is 100 points.
The 70% mean means that the mean for the 30 students was 70 points. That means 2100 points were scored between all 30 students. (70·30=2100)
20 boys had a mean of 62% or 62 points for our test. That means the boys earned 62·20 points, or 1240 points.
That then means the girls earned 2100 - 1240 points, or 860 points.
Since there are 10 girls, 860/10 = 86 or 86% mean on the test.
Girls rock!
8.275.
If you add both and divide by two you get 8.275
Answer:
A. 2.5 standard deviations below the average salary.
Step-by-step explanation:
In a normally distributed sample, the z-score measure how many standard deviations a measure is above or below the mean.
If the zscore is positive, the measure is above the mean.
If it is negative, the measure is below the mean.
A quality control specialist calculated thez-score associated with his own salary and found it was minus2.50. What is his salary?
This means that his salary is 2.5 standard deviations below the mean, that is the average salary.
The correct answer is A.
