SOLUTION: 1) A poll was done where 450 adults were randomly surveyed. 35 % said they were working hard at their jobs and hoped to get a promotion. Calculate and interpret a 95 % confidenc

Algebra ->  Probability-and-statistics -> SOLUTION: 1) A poll was done where 450 adults were randomly surveyed. 35 % said they were working hard at their jobs and hoped to get a promotion. Calculate and interpret a 95 % confidenc      Log On


   

Question 1157864: 1) A poll was done where 450 adults were randomly surveyed. 35 % said they were working hard at their jobs and hoped to get a promotion. Calculate and interpret a 95 % confidence interval for the proportion of adults who said they were working hard and hoped for a promotion.
A) p - hat =
Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
x = 0.35*450 = 157.5, which is not a whole number of people, so we round up to
158.  (some teachers say to round down.  You'll have to ask your teacher. Maybe
he or she wants you to round down to 157. It will make a difference in the third
decimal place of the interval bounds.) 

On your TI-84

Press STAT
Press right arrow key to highlight TESTS
Scroll down with down arrow key to 1-PropZInt...
Press ENTER
Make the screen read like this:

       1-PropZInt        
x:158
n:450
C-Level:0.95
Calculate

Use down arrow to highlight Calculate
Press ENTER

Read

(0.30701,0.39521)
p̂=0.3511111111
n-450

The confidence interval is 0.30701 < p < 0.39521

Edwin