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2 years ago

Simplify to create an equivalent expression.

Mathematics

1 answer:

Natalka [10]2 years ago

6 0

Answer:

$\boxed{ \bold{ \huge{ \boxed{ \sf{30t - 4}}}}}$

Choice C is correct.

Step-by-step explanation:

$\sf{2 - 6( - 5t + 1)}$

Distribute -6 through the parentheses

$\longrightarrow{ \sf{2 + 30t - 6}}$

The negative and positive integers are always subtracted but posses the sign of the bigger integer

$\longrightarrow{ \sf{30t - 4}}$

Hope I helped!

Best regards! :D

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The scientist performs additional analyses and observes that the number of major earthquakes does appear to be decreasing but wo

kifflom [539]

Answer:

Step-by-step explanation:

Hello!

A regression model was determined in order to predict the number of earthquakes above magnitude 7.0 regarding the year.

^Y= 164.67 - 0.07Xi

Y: earthquake above magnitude 7.0

X: year

The researcher wants to test the claim that the regression is statistically significant, i.e. if the year is a good predictor of the number of earthquakes with magnitude above 7.0 If he is correct, you'd expect the slope to be different from zero: β ≠ 0, if the claim is not correct, then the slope will be equal to zero: β = 0

The hypotheses are:

H₀: β = 0

H₁: β ≠ 0

α: 0.05

The statistic for this test is a student's t: $t= \frac{b - \beta }{Sb} ~~t_{n-2}$

The calculated value is in the regression output $t_{H_0}= -3.82$

This test is two-tailed, meaning that the rejection region is divided in two and you'll reject the null hypothesis to small values of t or to high values of t, the p-value for this test will also be divided in two.

The p-value is the probability of obtaining a value as extreme as the one calculated under the null hypothesis:

p-value: $P(t_{n-2}\leq -3.82) + P(t_{n-2}\geq 3.82)$

As you can see to calculate it you need the information of the sample size to determine the degrees of freedom of the distribution.

If you want to use the rejection region approach, the sample size is also needed to determine the critical values.

But since this test is two tailed at α: 0.05 and there was a confidence interval with confidence level 0.95 (which is complementary to the level of significance) you can use it to decide whether to reject the null hypothesis.

Using the CI, the decision rule is as follows:

If the CI includes the "zero", do not reject the null hypothesis.

If the CI doesn't include the "zero", reject the null hypothesis.

The calculated interval for the slope is: [-0.11; -0.04]

As you can see, both limits of the interval are negative and do not include the zero, so the decision is to reject the null hypothesis.

At a 5% significance level, you can conclude that the relationship between the year and the number of earthquakes above magnitude 7.0 is statistically significant.

I hope this helps!

(full output in attachment)

5 0

3 years ago

The table represents the temperature of a cup of coffee over time.

Harrizon [31]

Answer: first choice, exponential, because there is a relatively consistent multiplicative rate of change.

Explanation:

1) I have attached the figure with the data table that represents the temperature of a cup of coffee over time.

These are the data:

Time (min) ------ Temperature (°F)

0 ----------------------- 200

10 ---------------------- 180

20 --------------------- 163

30 --------------------- 146

40 ---------------------131

50 -------------------- 118

60 -------------------- 107

2) Since, the increase in time is constant, while the decrease in temperaute is not, you know that it is not linear.

3) The other two options involve exponential models.

The exponential models have a constant multiplicative rate of change, not additive. Therefore, the only feasible choice is the first one: temperature of a cup of coffee over time.

4) You can prove it:

i) Exponential models have the general form y = A [r]ˣ, where B is r is the multiplicative rate of change: any value is equal to the prior value multiplied by r:

y₁ = A [r]¹

y₂ = A[r]²

y₂ / y1 = r ← as you see this is the constant multiplicative rate of change.

ii) Test some data:

180 / 200 = 0.9

163 / 180 ≈ 0.906 ≈ 0.9

146 / 163 ≈ 0.896 ≈ 0.9

131 / 146 ≈ 0.897 ≈ 0.9

118 / 131 ≈ 0.901 ≈ 0.9

107 / 118 ≈ 0.907 ≈ 0.9

As you see all the data of the table have a relatively consistent multiplicative rate of change, which proves that the temperature follows an exponential decay; so the right choice is the first one.

6 0

2 years ago

Read 2 more answers

Express the confidence interval 0.555 less than 0.777 in the form Modifying above p with caret plus or minus Upper E.

Elina [12.6K]

Complete Question

Express the confidence interval 0.555 less than p less than 0.777 in the form Modifying above p with caret plus or minus Upper E.

Answer:

The modified representation is $\r p \pm E = 0.666 \pm 0.111$

Step-by-step explanation:

From the question we are told that

The confidence interval interval is $0.555 < p < 0.777$

Now looking at the values that make up the up confidence interval we see that this is a symmetric confidence interval(This because the interval covers 95% of the area under the normal curve which mean that the probability of a value falling outside the interval is 0.05 which is divided into two , the first half on the left -tail and the second half on the right tail as shown on the figure in the first uploaded image(reference - Yale University ) ) which means

Now since the confidence interval is symmetric , we can obtain the sample proportion as follows

$\r p = \frac{0.555 + 0.777}{2}$

$\r p =0.666$

Generally the margin of error is mathematically represented as

$E = \frac{1}{2} * K$

Where K is the length of the confidence interval which iis mathematically represented as

$K = 0.777 -0.555$

$K = 0.222$

Hence

$ME = \frac{1}{2} * 0.222$

$ME = 0.111$

So the confidence interval can now be represented as

$\r p \pm E = 0.666 \pm 0.111$

3 0

3 years ago

Please say me the answer fast with step by step process

zepelin [54]

Yes I’m sorry but I’m sorry I’m texting back to my sister in

8 0

3 years ago

A regular hexagon has an area of 750.8 cm. The side length is 17 cm. Find the apothem.

kompoz [17]

Since, a regular hexagon has an area of 750.8 square cm and The side length is 17 cm.

We have to find the apothem of the regular hexagon.

The formula for determining the apothem of regular hexagon is $s \div {{2 \tan (\frac{180}{n})}$ , where 's' is any side length of regular hexagon and 'n' is the number of sides of regular hexagon.

So, apothem = $17 \div {2 tan(\frac{180}{6})$

= $17 \div {2 tan(30)$

= $17 \div {1.15}$

= 14.78 units

Therefore, the measure of apothem of the regular hexagon is 14.7 units.

Option B is the correct answer.

5 0

2 years ago