Answer:
a) The estimated standard deviation of the sampling distribution of the proportion is 0.023
b) the estimated standard deviation have been if he had surveyed only 100 customers is 0.046
Step-by-step explanation:
given information:
the number of sample, n = 400
sample proportion, p = 70% = 0.7
a) standard deviation of a sample proportion is
σ = [tex]\sqrt{\frac{p(1-p)}{n}}[/tex]
= [tex]\sqrt{\frac{0.7 (1-0.7)}{400} }[/tex]
= 0.023
b) if n = 100, so
σ = [tex]\sqrt{\frac{p(1-p)}{n}}[/tex]
= [tex]\sqrt{\frac{0.7 (1-0.7)}{100} }[/tex]
= 0.046
