A sample from a population with 40 and 10 has a mean of M

A sample from a population with = 40 and = 10 has a mean of M = 44. If the sample mean corresponds to a z = 2.00, then how many scores are in the sample?

Mean ( u ) =40
Standard Deviation ( sd )=10
Number ( n ) = 1000Normal Distribution = Z= X- u / (sd/Sqrt(n) ~ N(0,1)
Z = (44-40)/10/ Sqrt ( n )
2 = 4 / (10/ Sqrt ( n ))
Sqrt ( n ) = 10*2 / 4 = 5
n= 25