Simplify the radical expression by rationalizing the denominator.

Mathematics

1 answer:

artcher [175]2 years ago

4 0

$\frac{4}{\sqrt{21}} = \frac{4}{\sqrt{21}} \times \frac{\sqrt{21}}{\sqrt{21}} =\boxed{ \frac{4\sqrt{21}}{21}}$

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2 half dollars = how many dimes

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Mary and Jane both took PSY230 last semester but they were in two different sections taught by different professors. Mary's clas

Greeley [361]

Answer:

Due to the higher z-score, Jane did better in class.

Step-by-step explanation:

Z-score:

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question:

Whoever's grade had the better z-score did better in class.

Mary's:

Mean of 85, standard deviation of 5, grade of 88. This means that $\mu = 85, \sigma = 5, X = 88$ . So