Question

People were polled on how many books they read the previous year. How many subjects are needed to estimate the number of books read the previous year within one book with 95?% ?confidence? Initial survey results indicate that sigmaequals10.6 books. A 95 % confidence level requires nothing subjects. ?(Round up to the nearest whole number as? needed.)

Answer 1

Solution :

Given that,

standard deviation = = 10.6

margin of error = E = 1

At 95% confidence level the z is ,

= 1 - 95% = 1 - 0.95 = 0.05

/ 2 = 0.05 / 2 = 0.025

Z_/2 = Z_0.025 = 1.96

Sample size = n = ((Z_/2 * ) / E)²

= ((1.96 * 10.6) / 1)²

= 431.64 = 432

Sample size = 432 subjects .