Question

Chapter 17 Written Assignment Name 1. The adoption of smart phones has been discussed a lot. One aspect of these devices is that students tend to be distracted by their phones during class. A recent survey reported that 76 % of 1004 randomly sampled females used their smart phones during class time, compared to 71% of 1009 randomly sampled males. Do these results confirm a higher smart phone usage by females? a) (16 points) State and test an appropriate hypothesis and state your conclusions. Show your work, including checking the assumptions and conditions b) (6 point) Find a 99% confidence interval for the difference in the proportion of males and females who use their phone during class. Interpret your interval

Answer 1

. We have given :- tet nie sample size for & females = 1004 º = 761. 30.46 4 na = sample size for males = 1009 P = 71.1. =0.71 claim . Do these results confirm a higher smont phone usage by Females. a) To Test : Ho: P, = P21 vs M, P, 7P2. P.. Popwahon propostion for females of

P2 = Population proportion for males. Test statistic : z= (P - P2) -P;) + 12+ (1-12) na here a rest as the condition sulisty .(sample size is large) ż= 0.05 C0.76 – 0.71) 0.767(1-0-76) + V 1004 10.71*11-0. 41) 1009 100.000 181 + 0.000204) 0.05 = 2.5480] 0.01962

hese d=99% critical value = 22 here test is right fail : 30/=2-33 (from table) Decision :- we reject Ho if z fest statistic > - za here 2 fest stahishic > za here - we reject Ho at x=99%. conclusion in There is enough evidence to conclude that a higher smart phone usage by remules 1. at 2=99 % © 997. confidence interval for the difference - in the proportion of males d females

cư, -) + ( ( 4 ) + ( 4 + 4 42 ) [p?q=3] 4 . 9-1-P) 1.3612 E $2:58) -(from table) =[ 0.05 1 (2:58 +0.01462)] = [o-os f 0.015061) = (-0.00061, 0-10061) - (99;. confident that the difference in the proportion of males f females is lies within -0.0006 to 0.10061) ® result may be 1. different from testing & confidence internal