Question

A study is being conducted on critics opinions of the new Addam's Family movie. Out of 112 critic reviews, 45 were positive.

A. Construct a 95% confidence interval for the percentage of critics that had a positive opinion of the movie.

B. Another website polled critics score of the movie (from 1-100) and found that out of 32 reviews, the average score for the movie was 46. Assume the stdev of ALL critics scores is 15 Construct a 90% confidence interval for the mean critic score of the movie.

C. In the setting described in part b), how many critic scores would we need in order to obtain a margin of error no greater than 1? (If can't be done, say so)

Answer 1

Solution X-45 n 112 A) Giren:- 45 0.40 X esimate ( Point 112 At gs . Confid ence Jevel, B1 using 2 table 2 4/z -Zo.025 .96 95 % Contidemce interval for mean is At t 21 * 2221 # Pal2 P. 0.-4०८।-०'५० ). 40 + 196 112 040 t 0og 0.49 CIE(0.31/ -49) Givems 46, S15 n 32 df n- t df 31 A 90 % Contd eme level isa0dt T S do 1-0.90 taprde to-os73t 1696

At 9o% ConAdence intenve tor mean is 46 t 1696 1S 46 t 4.49 (41.51, 50.49) (41.51, 50.4 CI margin of eror (E) = 15 Sample size (n)- t df S 1-696 15 6 47 SAmrle sige (n