The 47th Annual PDK/Gallup Poll of the Public’s Attitudes toward the Public Schools, conducted in May 2015, sampled 4,500 adult Americans and found that 64% feel there is too much emphasis on standardized testing in the public schools in their community. Using the quick method, the estimated margin of error for conclusions having 95% confidence about the entire adult population of adult Americans is ___%?

1.3809%

Step-by-step explanation:

Given ;

Sample size, n = 4500

Phat = 64% = 0.64

The margin of error :

Zcritical * √[Phat(1 - Phat) / n]

At 95% confidence level:

Zcritical at 95% = 1.96

Margin of Error :

1.96 * √[0.64(0.36) / 4500]

1.96 * 0.0071554

= 0.0138099

= 0.0138099 * 100%

= 1.3809%

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1

sounds & other waves originate from any vibrating object