Answer:

Step-by-step explanation:







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6.11
see- .8 .9 .10 so its .11
It's 180-50-50=180-100=80°
Here is dependence between scores and x-values:

where
is the mean,
is standard deviation and i changes from 1 to 2.
1. When i=1,
then

2. When i=2,
then

Now solve the system of equations:


Subtract first equation from the second:

Then

Answer: the mean is 62, the standard deviation is 20.