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2 years ago

Simplify each sum or difference. State any restrictions on the variables.

Mathematics

1 answer:

Dvinal [7]2 years ago

7 0

Answer:

2(d-2)/(2d+1) or 1 - 5/(2d+1)

d can not be -½

Step-by-step explanation:

(d-3)/(2d+1) + (d-1)/(2d+1)

Lcm: 2d+1

(d-3+d-1)/(2d+1)

= (2d-4)/(2d+1)

= 2(d-2)/(2d+1)

If further simplification required:

= (2d-4)/(2d+1)

= (2d+1-5)/(2d+1)

= (2d+1)/(2d+1) - 5/(2d+1)

= 1 - 5/(2d+1)

2d+1 = 0

When d = -½

So d can not be -½ because when the denominator becomes 0, fraction becomes undefined

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2 years ago

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Step-by-step explanation:

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2 years ago

A manufacturer of banana chips would like to know whether its bag filling machine works correctly at the 402 gram setting. It is

lidiya [134]

Answer:

The value of t test statistics is -2.25.

Step-by-step explanation:

We are given that a manufacturer of banana chips would like to know whether its bag filling machine works correctly at the 402 gram setting. It is believed that the machine is under filling the bags.

A 25 bag sample had a mean of 393 grams with a standard deviation of 20.

Let $\mu$ = mean filling of bags by the machine.

So, Null Hypothesis, $H_0$ : $\mu \geq$ 402 gram {means that the the machine is not under filling the bags}

Alternate Hypothesis, $H_A$ : $\mu$ < 402 gram {means that the the machine is under filling the bags}

The test statistics that would be used here One-sample t test statistics as we don't know about the population standard deviation;

T.S. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean bag filling = 393 grams

s = sample standard deviation = 20 grams

n = sample of bags = 25

So, test statistics = $\frac{393-402}{\frac{20}{\sqrt{25} } }$ ~ $t_2_4$

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The value of t test statistics is -2.25.

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3 years ago

PLEASE HELP ASAP!!! CORRECT ANSWER ONLY PLEASE!!!

Nadya [2.5K]

Answer: b) rolled three times, number of 2s rolled

d) rolled twice, number of odds rolled

Step-by-step explanation:

A binomial experiment must meet the following criteria:

There must be a fixed number of trials (rolls)
Each trial (roll) is independent of the others
There are only two outcomes (success or fail)
The probability of each outcome remains constant from trial to trial

a) rolled twice --> satisfies #1 & #2 (n = 2)

X is the sum --> fails #3 (more than two outcomes)

b) rolled three times --> satisfies #1 & #2 (n = 3)

X is the number of 2s rolled --> satisfies #3 & #4 (P success = 1/6)

c) rolled an unknown number of times - fails #1

d) rolled twice --> satisfies #1 & #2 (n = 2)

X is the number of odds rolled --> satisfies #3 & #4 (P success = 1/2)

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3 years ago

Suppose a 2011 Gallup poll revealed that 76% of Americans believe that high achieving students should be recruited to become tea

k0ka [10]

Answer:

95% Confidence interval: (0.73,0.79)

Step-by-step explanation:

We are given the following in the question:

Sample size, n = 1021

Percentage of Americans believe that high achieving students should be recruited to become teachers

$\hat{p} = 76\% = 0.76$

95% Confidence interval:

$\hat{p}\pm z_{stat}\sqrt{\dfrac{\hat{p}(1-\hat{p})}{n}}$

$z_{critical}\text{ at}~\alpha_{0.05} = \pm 1.96$

Putting the values, we get:

$0.76\pm 1.96(\sqrt{\dfrac{0.76(1-0.76)}{1021}})\\\\ = 0.76\pm 0.0261\\=(0.7339,0.7861)\\\approx (0.73,0.79)$

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3 years ago