The confidence interval is
.
This means that if we take repeated samples, 99% of the intervals would contain the population proportion.
To construct this interval, we use
,
where
Since 590/1016 said they had a cat and a dog, p=0.581 and N=1016:
We need the z-score associated with this confidence level:
Convert 99% to a decimal: 99/100 = 0.99
Subtract from 1: 1-0.95 = 0.01
Divide by 2: 0.01/2 = 0.005
Subtract from 1: 1-0.005 = 0.995
Using a z-table, we see that this value is equally distant from z=2.57 and z=2.58, so we will use z=2.575:
I hope this helps you
?=10×10
?=100
18.5-0.5= 18
18/3= 6
So r=6
Part A)
Total stores = 362 + 66 = 428
362 / 428 = 0.845 = 84.5% = 85%
66 / 428 = 0.154 = 15.4% = 15%
Yes this is consistent with the percentages shown in the first table.
Part B)
Total stores : 197 +115 = 312
197 / 312 = 0.631 = 63.1% = 63%
115 / 312 = 0.368 = 36.8% = 37%
The percentage for current stores is less than what is shown in the first table, so this would not be consistent.
Part C )
Percentage of new stores for the Northeast = 60 / 310 = 19%
The percentage of new stores for The Midwest and Northeast are below 25%, but the percentage of new stores in the South is above 25%, so the additional training wouldn't be required for the South, but should be required for the other two areas.
She estimated by rounding 907 -> 900 and 626 -> 630 and when you subtract them, you get 270, which is how she estimated >300 people would arrive in the afternoon