What’s the answer to -3/4+9/10 simplified ?

1 answer:

6 0

1) -3•5/ 4•5 And 9•2/ 10•2 Because you want to have the same denominator. That equals -15/20 + 18/20 so you just add -15+18 to get 3/20
The answer is 3/20

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You want to obtain a sample to estimate a population proportion. At this point in time, you have no reasonable preliminary estim

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Using the z-distribution, it is found that a sample size of 3,385 is required.

<h3>What is a confidence interval of proportions?</h3>

A confidence interval of proportions is given by:

$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

The margin of error is:

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which:

$\pi$ is the sample proportion.

z is the critical value.

n is the sample size.

In this problem, we have a 98% confidence level, hence $\alpha = 0.98$ , z is the value of Z that has a p-value of $\frac{1+0.98}{2} = 0.99$ , so the critical value is z = 2.327.

We have no prior estimate, hence $\pi = 0.5$ is used, which is when the largest sample size is needed. To find the sample size, we solve the margin of error expression for n when M = 0.02, hence: