A sample of 1700 computer chips revealed that 73% of the chips do not fail in the first 1000 hours of their use. The company's promotional literature claimed that more than 70% do not fail in the first 1000 hours of their use. Is there sufficient evidence at the 0.05 level to support the company's claim?

Solution :

It is a left tailed test.

Given : n = 1700

α = 0.05

We want to test,

the null hypothesis,  

the alternate hypothesis,

Test statistics is

Thus z - critical value = 1.64

Since, z calculated  -----  z-critical value

             (2.70)                          (1.64)

Thus we reject the null hypothesis.

So there is sufficient evidence at 0.05 level to support the company's claim that more the 70% do not fail in the first 1000 hours of their use.

the polynomial is a perfect square trinomial of the form a^2-2ab+b^2:

option a. true

step-by-step explanation:

9x^2-12x+4

comparing with the form a^2-2ab+b^2

1.) a^2=9x^2

solving for a: square root both sides of the equation:

sqrt(a^2)=sqrt(9x^2)

a=sqrt(9) sqrt(x^2)

a=3x

2.) b^2=4

solving for b: square root both sides of the equation:

sqrt(b^2)=sqrt(4)

b=2

to be a perfet square trinomial 2ab must be equal to 12x. let's check:

2ab = 2 (3x) (2)

2ab = 12x

correct

the one below it is a function