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3 years ago

How do I add fractions with different denominations?

1 answer:

7 0

1.Write down the fractions.
2.Find a common denominator.
3.Multiply both numbers on the first fraction by the bottom number of the second fraction.
4.Multiply both numbers on the second fraction by the bottom number of the first fraction.
5.Line both fractions up side by side with their new numbers.
6.Add together the numerators of the two fractions.
7.Take the common denominator that you figured out in Step 2 and add it on the bottom of your new numerator.
8.Put the new numerator on top and the new denominator on bottom.
9.Simplify and reduce.

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A studio is buying four (4) MP3 players for $129.55 each. Estimate the least number of $100 bills needed to buy the MP3 players.

Dahasolnce [82]

Answer:

6 bills

Step-by-step explanation:

129.55*4 = $518.20

you have to round up since it is over $500 so its 6 $100 bills

8 0

3 years ago

Read 2 more answers

Find one positive and one negative angle coterminal with an angle of <img src="https://tex.z-dn.net/?f=%5Cfrac%7B11pi%7D%7B8%7D"

zaharov [31]

Answer:

see explanation

Step-by-step explanation:

Co terminal angles are angle ± 2π, that is

$\frac{11\pi }{8}$ + 2π

= $\frac{11\pi }{8}$ + $\frac{16\pi }{8}$ = $\frac{27\pi }{8}$

and

$\frac{11\pi }{8}$ - 2π

= $\frac{11\pi }{8}$ - $\frac{16\pi }{8}$ = - $\frac{5\pi }{8}$

3 0

4 years ago

The Salk polio vaccine experiment in 1954 focused on the effectiveness of the vaccine in combating paralytic polio. Because it w

sdas [7]

Answer:

Step-by-step explanation:

Hello!

The variables of interest are:

X₁: Number of cases of polio observed in kids that received the placebo vaccine.

n₁= 201299 total children studied

x₁= 110 cases observed

X₂: Number of cases of polio observed in kids that received the experimental vaccine.

n₂= 200745 total children studied

x₂= 33 cases observed

These two variables have a binomial distribution. The parameters of interest, the ones to compare, are the population proportions: p₁ vs p₂

You have to test if the population proportions of children who contracted polio in both groups are different: p₂ ≠ p₁

H₀: p₂ = p₁

H₁: p₂ ≠ p₁

α: 0.05

$Z= \frac{(p'_2-p'_1)-(p_2-p_1)}{\sqrt{p'[\frac{1}{n_1} +\frac{1}{n_2} ]} }$

Sample proportion placebo p'₁= x₁/n₁= 110/201299= 0.0005

Sample proportion vaccine p'₂= x₂/n₂= 33/200745= 0.0002

Pooled sample proportion p'= (x₁+x₂)/(n₁+n₂)= (110+33)/(201299+200745)= 0.0004

$Z_{H_0}= \frac{(0.0002-0.0005)-0}{\sqrt{0.0004[\frac{1}{201299} +\frac{1}{200745} ]} }= -4.76$

This test is two-tailed, using the critical value approach, you have to determine two critical values:

$Z_{\alpha/2}= Z_{0.025}= -1.96$

$Z_{1-\alpha /2}= Z_{0.975}= 1.96$

Then if $Z_{H_0}$ ≤ -1.96 or if $Z_{H_0}$ ≥ 1.96, the decision is to reject the null hypothesis.

If -1.96 < $Z_{H_0}$ < 1.96, the decision is to not reject the null hypothesis.

⇒ $Z_{H_0}$ = -4.76, the decision is to reject the null hypothesis.

H₀: p₂ = p₁

H₁: p₂ ≠ p₁

α: 0.01

$Z= \frac{(p'_2-p'_1)-(p_2-p_1)}{\sqrt{p'[\frac{1}{n_1} +\frac{1}{n_2} ]} }$

The value of $Z_{H_0}$ = -4.76 doesn't change, since we are working with the same samples.

The only thing that changes alongside with the level of significance is the rejection region:

$Z_{\alpha /2}= Z_{0.005}= -2.576$

$Z_{1-\alpha /2}= Z_{0.995}= 2.576$

Then if $Z_{H_0}$ ≤ -2.576or if $Z_{H_0}$ ≥ 2.576, the decision is to reject the null hypothesis.

If -2.576< $Z_{H_0}$ < 2.576, the decision is to not reject the null hypothesis.

⇒ $Z_{H_0}$ = -4.76, the decision is to reject the null hypothesis.

Remember the level of significance (probability of committing type I error) is the probability of rejecting a true null hypothesis. This means that the smaller this value is, the fewer chances you have of discarding the true null hypothesis. But as you know, you cannot just reduce this value to zero because, the smaller α is, the bigger β (probability of committing type II error) becomes.

Rejecting the null hypothesis using different values of α means that there is a high chance that you reached a correct decision (rejecting a false null hypothesis)

I hope this helps!

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3 years ago

What is the LCM of 9 and 21?

Naddik [55]

The least common multiple is 63

3 0

3 years ago

Read 2 more answers

the sales tax in bill's state is 6%. bill bought a scion having a sales tax of $820. what was the cost of the car? round to the

polet [3.4K]

Since there is a sales tax of 6% which was equal to $820

Let the value be = x

6% of x = 820

(6/100)x = 820

0.06x = 820

x = 820/0.06

x = 13666.67

Value to the nearest dollar ≈ $13 666.67

7 0

3 years ago