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3 years ago

8

A 95% confidence is given by (15,20) . The interval is based on a sample of size n=25 .

1 answer:

love history [14]3 years ago

5 0

Answer:

b. quadruple the sample size.

Step-by-step explanation:

Given that a 95% confidence is given by (15,20) .

this implies that mean = average of lower and higher bounds of confidence interval = $\frac{15+20}{2} =17.5$

Margin of error = Upper bound - Mean = $20-17.5 = 2.5$

Confidence level = 95%

Critical value = 1.96

Std error = $\frac{2.5}{1.96} =1.27551$

Std devition = Std error * sqrt n = 6.3775

If we want to reduce margin of error by half we must get margin of error as 1.25

For that std error for same critical value = 0.63775

Std deviation did not change

So sample size only changed which implies that sample size is 4 times the original

b. quadruple the sample size.

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Answer:

He must invest R297 521 today.

Step-by-step explanation:

The compound interest formula is given by:

$A(t) = P(1 + \frac{r}{n})^{nt}$

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This means that $t = 2, A(t) = 350000$

Interest rate of 8.15% per annum compounded monthly:

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3 years ago

Simplify each expression:<br> ( 5a^2b^3)(4ab^5)

DIA [1.3K]

Answer:

(22•5a3b4)

Step-by-step explanation:

STEP

1

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Equation at the end of step 1

4ab • (5a2 • b3)

STEP

2

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Multiplying exponential expressions :

2.1 a1 multiplied by a2 = a(1 + 2) = a3

Multiplying exponential expressions :

2.2 b1 multiplied by b3 = b(1 + 3) = b4

Final result :

(22•5a3b4)

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2 years ago

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