How can i make 0.48 into a fraction

0.48 = 48/100 =12/25
Hope it helps

The standard deviation in the case is 0.004.

The population mean is 25.01 and the population standard deviation is 0.002.  To find the sample standard deviation, we use 
σₓ = σ/(√n), where σ is the population standard deviation and n is the sample size.  Using our information we have:
σₓ = 0.02/(√24) = .004.