In a certain data distribution, 85 is 0.25 standard deviation above the mean and 50 is 1.5 standard deviations below the mean. What value is 0.75 standard deviation below the mean

The mean is 80 and the standard deviation is 20. Therefore we have

65 is 0.75 standard deviation below the mean.

Step-by-step explanation:

z =

Since 85 is 0.25 standard deviations above the mean we have

or 0.25·σ  = 85 - μ......1

1.5 = or 1.5·σ  = μ - 50..............2

From 1 we have σ = 340 - 4·μ substituting into 2 gives

1.5·(340 - 4·μ) =  μ - 50 ⇒ 510 - 6·μ = μ - 50

7·μ = 560 or μ = 80

Therefore σ = 340 - 4·μ = 340 - 4·80 = 20

A value, x, 0.75 standard deviation below the mean is given by

0.75 = which gives 15 = 80 - x or

x = 65.

answer: i'm not sure

step-by-step explanation:

10.416 m/s

step-by-step explantion:

distance=100m

time= 9.6s

average speed=100/9.6

=10.416 m/s