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2 years ago

Point (-4,-8) Reflected across the y-axis

Mathematics

1 answer:

nekit [7.7K]2 years ago

5 0

Answer:

(4,-8)

Step-by-step explanation:

Where is the point on the opposite side of the y-axis?

The answer would be (4, -8)

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2 years ago

What is the answer to y=2•2^x

KATRIN_1 [288]

Answer:

y=4^x

Step-by-step explanation:

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3 years ago

Find the distance between the two points rounding to the nearest tenth (if necessary).

kap26 [50]

Answer:

4.5

Step-by-step explanation:

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3 years ago

Student records suggest that the population of students spends an average of 6.30 hours per week playing organized sports. The p

Ymorist [56]

Answer:

a) 99.24% chance HLI will find a sample mean between 5.5 and 7.1 hours.

b) 81.64% probability that the sample mean will be between 5.9 and 6.7 hours.

Step-by-step explanation:

To solve this question, it is important to know the Normal probability distribution and the Central Limit Theorem

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

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.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a random variable X, with mean $\mu$ and standard deviation $\sigma$ , a large sample size can be approximated to a normal distribution with mean $\mu$ and standard deviation $\frac{\sigma}{\sqrt{n}}$ .

In this problem, we have that:

$\mu = 6.3, \sigma = 2.1, n = 49, s = \frac{2.1}{\sqrt{49}} = 0.3$

A) What is the chance HLI will find a sample mean between 5.5 and 7.1 hours?

This is the pvalue of Z when X = 7.1 subtracted by the pvalue of Z when X = 5.5.

By the Central Limit Theorem, the formula for Z is:

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

X = 7.1

$Z = \frac{7.1 - 6.3}{0.3}$

$Z = 2.67$

$Z = 2.67$ has a pvalue of 0.9962

X = 5.5

$Z = \frac{5.5 - 6.3}{0.3}$

$Z = -2.67$

$Z = -2.67$ has a pvalue of 0.0038

So there is a 0.9962 - 0.0038 = 0.9924 = 99.24% chance HLI will find a sample mean between 5.5 and 7.1 hours.

B) Calculate the probability that the sample mean will be between 5.9 and 6.7 hours.

This is the pvalue of Z when X = 6.7 subtracted by the pvalue of Z when X = 5.9

X = 6.7

$Z = \frac{6.7 - 6.3}{0.3}$

$Z = 1.33$

$Z = 1.33$ has a pvalue of 0.9082

X = 5.9

$Z = \frac{5.9 - 6.3}{0.3}$

$Z = -1.33$

$Z = -1.33$ has a pvalue of 0.0918.

So there is a 0.9082 - 0.0918 = 0.8164 = 81.64% probability that the sample mean will be between 5.9 and 6.7 hours.

5 0

3 years ago

Country Financial, a financial services company, uses surveys of adults age and older to determine if personal financial fitness

lesya692 [45]

Complete question :

Country Financial, a financial services company, uses surveys of adults age 18 and older to determine if personal financial fitness is changing over time (USA Today, April 4, 2012). In February of 2012, a sample of 1000 adults showed 410 indicating that their financial security was more than fair. In February of 2010, a sample of 900 adults showed 315 indicating that their financial security was more than fair. a. State the hypotheses that can be used to test for a significant difference between the population proportions for the two years. H : Pi - P2 - Select your answer HA : P1 P2 - Select your answer - b. What is the sample proportion indicating that their financial security was more than fair in 2012? Round your answer to two decimal places. In 2010?

Answer:

H0 : p1 - p2 = 0

H1 : p1 - p2 ≠ 0

Phat 2010 = 0.35

Phat 2012 = 0.41

Step-by-step explanation:

The null and alternative hypothesis :

H0 : p1 - p2 = 0

H1 : p1 - p2 ≠ 0

The null means there is no difference in proportion for the two years while the alternative claims that there is difference in proportion for the two years.

Sample proportion for 2010:

Phat = x / n

x = 315 ; n = 900

Phat = 315 / 900

Phat = 0.35

Sample proportion for 2012 :

Phat = x / n

x = 410 ; n = 1000

Phat = 410 / 1000

Phat = 0.41

6 0

2 years ago