It has been observed that some persons who suffer colitis, again suffer colitis within one year of the first episode. this is due, in part, to damage from the first episode. the performance of a new drug designed to prevent a second episode is to be tested for its effectiveness in preventing a second episode. in order to do this two groups of people suffering a first episode are selected. there are 118 people in the first group and this group will be administered the new drug. there are 127 people in the second group and this group wil be administered a placebo. after one year, 12% of the first group has a second episode and 13% of the second group has a second episode. select a 90% confidence interval for the difference in true proportion of the two groups. a) [-0.060, -0.043] b) [-0.080, 0.060] c) [-0.093, 0.073] d) [-0.580, 0.560] e) [-0.073, 0.093] f) none of the above

b) [-0.080, 0.060]

Step-by-step explanation:

The confidence interval for the difference in true proportion of the two groups. is given by :-

, where = Sample size for first group.

= Sample size for second group.

= Sample proportion for first group.

= Sample proportion for second group.

z* = critical z-value.

As per given , we have

,  ,  ,

Critical value for 90% confidence interval is 1.645. (By z-table)

Substitute all values in formula , we get

Hence, the 90% confidence interval for the difference in true proportion of the two groups. is (-0.080, 0.060)

Hence, the correct answer is b) [-0.080, 0.060]

this story was prepared by jim

mccullaugh in los angeles and

al stewart in new york.

new york the colossal success of "top gun" appears to have dramatically altered madison avenue's

perception of corporate sponsorship

of home video projects.

the paramount home video re- lease, featuring a 60- second diet

pepsi spot, was by no means the

first prerecorded video to carry an advertiser's plug, but it was the

first major theatrical release to do so. in the aftermath of the title's

success, paramount is widely ex- pected to ink a similar deal for

"crocodile dundee" or "star trek

iv" or both.

corporate america's new attraccds push british

recording sales

to 19% gain

london fueled by the compact

disk boom, the value of u.k. manu- facturer shipments of recordings

rose 19% in the 12 -month period ended march 1987, according to the

british phonographic industry.

total value of u.k. shipments for

the period was $755 million for all

configurations. (all value figures

are based on an exchange rate of

$1.68 to the pound sterling.)

cd sales totaled 10.7 million units

worth $121.3 million- compared

with 3.7 million units worth $39.5

million in the prior 12 months -and

accounted for two -thirds of the

overall gain in trade value. at present growth rates, says the bpi, cd

sales for calendar 1987 will reach 20

(continued on page 79)

step-by-step explanation:

i think the answer would be c