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.
4,200+525(5×12)
4,200+525(60)=
4,200+31,500=35,700
Answer:
x = 64 m
Step-by-step explanation:
The scale is proportional to the actual:
(6 m)/(3/4 cm) = x/(8 cm)
Multiplying by 8 cm, we get ...
x = (8 cm)·(6 m)/(3/4 cm)
x = 64 m . . . . the width of the actual wall
Answer: r=6
Step-by-step explanation:
Because if 42 equals 7 times r you just have to divide 42 by 7.