Question

A sample of college students was asked whether they would return the money if they found a wallet on the street. Of the 93 women, 84 said "yes," and of the 75 men, 47 said "yes." Assume that these students represent all college students. (a) Find separate approximate 95% confidence intervals for the proportions of college women and college men who would say "yes" to this question. (Round the answers to three decimal places.) for women for men (b) Find an approximate 95% confidence interval for the difference in the proportions of college men and women who would say "yes" to this question. (Round the answers to three decimal places.) to (c) Complete the sentences interpreting the intervals in parts (a) and (b). The two separate intervals make it evident that the proportion is higher for the population of ---Select--- This is confirmed in part (b), because the interval for the difference in proportions does not include . , so we can conclude that a difference exists.

Answer 1

A)

84 х sample size sample proportion p 93.0 n x/n= 0.9030 std error V(p*(1-p)/n) -Se 0.0310 for 95 % Cl value of z 1.960 margin of error E=z*std error 0.061 lower confidence bound-sample proportion-margin of error 0.842 Upper confidence bound-sample proportion+margin of error 0.964

from above 95% CI: 0.842 to 0.964 for women

similarly: 0.517 to 0.737 for men

b)

men women 47 84 х, X2 0.6267 0.9032 75 93 n1 n2 estimated difference in proportion -0.2766 V(p (1-p/n+p2*(1-p2)/n2) std error Se 0.0637 for 95 % Cl value of z margin of error E=z*std error lower confidence bound 1.960 0.1249 -0.401 Upper confidence bound -0.152

\

95% CI =-0.401 to -0.152 ( please try 0.152 to 0.401 if this comes incorrect)

c)

the two seperate..........of women

does not include 0, so we can conclude.........