A variable of a population has a mean of n 300 and a standa

A variable of a population has a mean of n = 300 and a standard deviation of

Solution

a)
Mean ( u ) =300
Standard Deviation ( sd )= 42/ Sqrt ( 49 ) = 6
Normal Distribution = Z= X- u / (sd/Sqrt(n) ~ N(0,1)                  

b)
Normal Distribution

c)
B. No Because the distribution of the variable under consideration is not specified. a sample size of
at least 30 is needed for part (a) to be true

Reason: Unless it specified we don\'t assume that sample is under normal for size less than 30