Answer:
-3/25
Step-by-step explanation:
Solution :




= 178 x 0.48
= 85.44
≈ 85

= 427 x 0.38
= 162.26
≈ 162
a). Yes, the sample sizes are large enough to use the large sample confidence interval so as to estimate the difference in the population proportions.
Let 
Where the
the age
group and the 2 - subscript indicates the age
group.
Since 

are all at least 10, the sample sizes are large enough to use the large sample confidence interval.


= 0.409421


= 1 - 0.4094
= 0.5906
b). 90% confidence interval is







c). Zero is not included in the confidence interval. Answer is no. The difference in the two population proportion are different from each other.
Answer:
8.8 cm
Step-by-step explanation:
-We know that the top 20% of the books are oversized.
-We therefore find the z-value of the top 20%:

#We substitute the z value in formula to solve X.

Where
- X is the minimum thickness of the book.
-Given
, the minimum thickness,X can be calculated as follows:

Hence, the minimum thickness of the oversized books is 8.8 cm
A(x) = 3x - 12
b(x) = x - 9
a(b(x)) = a(x - 9) = 3(x - 9) - 12 = 3x - 27 - 12 = 3x - 39
a(b(x)) = 3x - 39