Question

On a test that has a normal distribution, a score of 41 falls three standard deviations below the mean, and a score of 73 falls one standard deviation above the mean. Determine the mean of this test.

Answer 1

its actually 35

Explanation:

Answer 2

The mean of the test is 65

Explanation:

Let the mean be x and SD be y

3 SD BELOW the mean means that we are taking away 3 SD FROM the mean

Mathematically, we have that as;

x - 3y = 41 •••••(i)

73 is 1 SD above mean

Mathematically;

x + y = 73 ••••••••(ii)

So let us solve both equations simultaneously

Simply multiply equation ii by 3 then add to i

x - 3y = 41

3x + 3y =219

4x = 41 + 219

4x = 260

x = 260/4

x = 65