Question

The 99% confidence interval for the mean, calculated from a sample of size n = 10 is 0.9390859 ≤ μ ≤ 5.460914 . Determine the sample mean X ¯ = (round to the first decimal place). Assuming that the data is normally distributed, determine the sample standard deviation s = (round to the first decimal place)

Answer 1

confidence interval is                  
lower limit =    0.9390859              
upper limit=   5.460914              
sample mean = (lower limit+upper limit)/2= (   0.9390859   +   5.460914   ) / 2 =   3.2

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margin of error = (upper limit-lower limit)/2= (   5.460914   -   0.9390859   ) / 2 =   2.26091405
                  
margin of error ,E = critical value(*s/√n )                  

α=   0.01
n=   10
  
critical value=   3.25
std dev = E*√n/critical value=   2.2