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3 years ago

Which of the following expressions correctly uses the properties of summations to represent

Mathematics

2 answers:

madam [21]3 years ago

8 0

Answer:

Option C is correct.

$7 \cdot \sum_{i=1}^{18} i^2 + 9 \cdot 18$

Step-by-step explanation:

Given the expression: $\sum_{i=1}^{18} (7i^2+9)$

Using properties of summation:

$\sum_{i=1}^{n} (a+bi) =\sum_{i=1}^{n} a + \sum_{i=1}^{n} bi$

$\sum_{i=1}^{n} a = an$

Using properties of summation in the given expression we have;

$\sum_{i=1}^{18} (7i^2+9)$

= $\sum_{i=1}^{18} 7i^2 + \sum_{i=1}^{18} 9$

= $7 \cdot \sum_{i=1}^{18} i^2 + 9 \cdot 18$

Therefore, the following given expression uses the properties of summation to represents is, $7 \cdot \sum_{i=1}^{18} i^2 + 9 \cdot 18$

masya89 [10]3 years ago

7 0

It is c but I don’t sure

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Answer:

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Step-by-step explanation:

The (1 - <em>α</em>)% confidence interval for the difference between population means is:

$CI=(\bar x_{1}-\bar x_{2})\pm z_{\alpha/2}\times \sqrt{\frac{\sigma^{2}_{1}}{n_{1}}+\frac{\sigma^{2}_{2}}{n_{2}}}$

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The critical value of <em>z</em> for 98% confidence level is,

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$CI=(\bar x_{1}-\bar x_{2})\pm z_{\alpha/2}\times \sqrt{\frac{\sigma^{2}_{1}}{n_{1}}+\frac{\sigma^{2}_{2}}{n_{2}}}$

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Answer:

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Step-by-step explanation:

According to my research on different types of sampling techniques, I can say that based on the information provided within the question the sampling technique used in this method is called a Convenience technique. This technique collects data from all the participants that were conveniently available to participate, and does not have any criteria that needs to be met. In this situation they used the data from all the participants that responded to the questionnaires, in other words the participants that were conveniently available,

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