(a+13)(a-8) using standard formulae expand

Mathematics

1 answer:

Viktor [21]3 years ago

4 0

The answer is a^2 + 5a - 104 I think

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1.) How many dessert combinations does Megan have?

Debora [2.8K]

Answer: I think

Step-by-step explanation:

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3 years ago

The high price of medicines is a source of major expense for those seniors in the United States who have to pay for these medici

Ilia_Sergeevich [38]

Answer:

$4600-1.646\frac{800}{\sqrt{1800}}=4568.96$

$4600+1.646\frac{800}{\sqrt{1800}}=4631.04$

We are confident at 90% that the true mean for the amount spent on medicines is between (4568.96 and 4631.04)

Step-by-step explanation:

Information given

$\bar X=4600$ represent the sample mean for the amount spent on medicines

$\mu$ population mean

s=800 represent the sample standard deviation

n=1800 represent the sample size

Solution

The confidence interval for the true population mean is given by:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

We can calculate the degrees of freedom with:

$df=n-1=1800-1=1799$

We know that the Confidence level is 0.90 or 90%, the value of significance is $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.05,1799)".And we see that $t_{\alpha/2}=1.646$