Answer:
68
Step-by-step explanation:
To get the sample size of the population, we will use the formula for calculating the standard error of the mean. This is expressed as;
SE = zσ/√n
z is the z score at 90% confidence
σ is the standard deviation
n is the sample size
SE is the mean weight loss
Given
z = 1.645
σ = 10
SE = 2
Required
sample size n
Substitute into the given equation;
SE = zσ/√n
2 = (1.645)(10)/√n
2 = 16.45/√n
√n = 16.45/2
√n = 8.225
n = (8.225)²
n = 67.650625
Hence the total sample should be about 68
