Answer:
The minimum sample needed to provide a margin of error of 3 or less is 52.
Step-by-step explanation:
The confidence interval for population mean (<em>μ</em>) is:

The margin of error is:

<u>Given:</u>
MOE = 3
<em>σ </em>= 11
The critical value for 95% confidence interval is: 
**Use the <em>z</em>-table for critical values.
Compute the sample size (<em>n</em>) as follows:

Thus, the minimum sample needed to provide a margin of error of 3 or less is 52.
Answer:
27
Step-by-step explanation:
Factory A proportion:
3 : 2,000
Factory B proportion:
5 : 4,500 (this can be simplified):
1 : 900
Now plug in 18,000 to each proportion:
Factory A:
x : 18,000
3 : 2,000
x = 27
Factory B:
x : 18,000
1 : 900
x = 20
Factory A had the greater amount of defects, 27
3m+4=1
subtract 4 on both sides
3m=-3
divide both sides by 3
m=-1
Oh all you do is however many numbers in the chart are the same. on the line put how many of each of them. like since there are three 7.5 in the 7.5 place you put how many there were.