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# 4=-2(×+3)please put the solutionthank ​

• Réponse publiée par: jemuelpogi

Hello !!

We need find the solution for

4 = -2(x+3).

4 = -2(x + 3)

4 = -2x - 6

2x = -6 - 4

2x = -10

x = -10/2

x = -5

Final result : the solution for (x) is -5.

I hope I have collaborated !

• Réponse publiée par: kuanjunjunkuan
Confidence interval for the population mean
z-test or normal distribution
solution:
given:
n=20, x̄ =89, s=2.0, 99%
formula:
x̄ -z_alpha/2(s/square root of n)< µ< x̄ +z_alpha/2(s/square root of n)
89-(2.575)(2.0/square root of 20)< µ< 89-(2.575)(2.0/square root of 20)
87.848< µ< 90.152

margin of error:
solution:
the critical value is 2.575.
the standard deviation is 2.0 (from the question), but as this is a sample, we need the standard error for the mean.
the formula for the se of the mean is  standard deviation / √(sample size), so: 2.0/ √(20)=0.447.
me=2.575 * 0.447 = 1.151.

therefore, the margin of error is 1.151  with the confidence interval of 87.848< µ< 90.152.
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4=-2(×+3)please put the solutionthank ​...