I conducted a poll and asked 1012 students how many books they read last year. The data indicates x = 12.1 books and s = 16.6 books. Construct a 90% confidence interval for the number of books the students read. Z = 1.645

(11.242 ; 12.958)

Step-by-step explanation:

The confidence interval is obtained using the relation :

C. I = xbar ± Zcritical * s/√n

Given that ::

xbar = 12.1 ;

Standard deviation, s = 16.6

n = 1012

C. I = 12.1 ± 1.645 * (16.6/√1012)

C.I = 12.1 ± 0.8583881

C. I = 11.242 ; 12.958

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step-by-step explanation:

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb