Write the mixed number as a fraction 3 2/3
2 answers:
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The confidence interval would be (10.44, 12.16). This means that if we take repeated samples, the true mean lies in 90% of these intervals.
To find the confidence interval, we use:
We first find the z-value associated with this. To do this:
Convert 90% to a decimal: 90% = 90/100 = 0.9
Subtract from 1: 1-0.9 = 0.1
Divide by 2: 0.1/2 = 0.05
Subtract from 1: 1-0.05 = 0.95
Using a z-table (http://www.z-table.com) we see that this is directly between two z-scores, 1.64 and 1.65; we will use 1.645:
To find the confidence interval, we use:
We first find the z-value associated with this. To do this:
Convert 90% to a decimal: 90% = 90/100 = 0.9
Subtract from 1: 1-0.9 = 0.1
Divide by 2: 0.1/2 = 0.05
Subtract from 1: 1-0.05 = 0.95
Using a z-table (http://www.z-table.com) we see that this is directly between two z-scores, 1.64 and 1.65; we will use 1.645:
Answer:
y intercept = -2
x intercepts = -2,-1,1
Step-by-step explanation:
f(x) = x^3 + 2x^2 -x-2
Set this equation equal to zero to find the x intercepts.
Factoring by grouping
0 =x^3 -x +2x^2 -2
= x( x^2-1) +2(x^2-1)
Factoring out the (x^2-1)
0= (x^2-1) (x+2)
Factoring the first term using the difference of squares (a^2-b^2) = (a-b)(a+b)
0 = (x-1) (x+1) (x+2)
Using the zero product property
x-1 = 0 x+1 = 0 x+2 =0
x=1, x=-1 x=-2
The x intercepts are -2, -1, 1
To find the y intercepts, set x=0
y = x^3 + 2x^2 -x-2
y = 0 -2
y = -2
