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2 years ago

9

In a math game rob reads four statements about the number 51. He has to pick up the true statement to win the game. Which statem

ent should rob choose

1 answer:

ozzi2 years ago

3 0

It is a prime number

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The Town of Hertfordshire clerk knows that 23% of dogs in the town have completed emotional support training. Hertfordshire plan

Nataly_w [17]

Answer:

95.64% probability that under 30% of the dogs are emotional support trained

Step-by-step explanation:

For each dog, there are only two possible outcomes. Either they have completed emotional support training, or they have not. So we use the binomial probability distribution to solve this problem.

However, we are working with samples that are considerably big. So i am going to aproximate this binomial distribution to the normal.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

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.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .

In this problem, we have that:

$\mu = E(X) = np = 100*0.23 = 23$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{100*0.23*0.77} = 4.21$

What is the probability that under 30% of the dogs are emotional support trained?

30% of 100 is 0.3*100 = 30

So this is the pvalue of Z when X = 30.

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

$Z = \frac{30 - 23}{4.1}$

$Z = 1.71$

$Z = 1.71$ has a pvalue of 0.9564.

So there is a 95.64% probability that under 30% of the dogs are emotional support trained

5 0

2 years ago

Suppose the average math SAT score for students enrolled at local community college is 490.4 with a standard deviation of 63.7.

lakkis [162]

Answer:

Option B) 9.1

Step-by-step explanation:

We are given the following in the question:

Average score = 490.4

Standard deviation = 63.7

Sample size, n = 49

Formula:

$=\dfrac{\sigma}{\sqrt{n}}$

Putting values, we get,

Standard error =

$=\dfrac{\sigma}{\sqrt{n}} = \dfrac{63.7}{\sqrt{49}} = 9.1$

Thus, the correct answer is

Option B) 9.1

8 0

2 years ago

Which of the following is a solution to the following system of inequalities?

iren2701 [21]

Option D: $(0,3)$ is the solution to the inequalities.

Explanation:

From the given graph, we can see that the equation of the inequalities are

$y>-x+1$ and $y\leq 2 x+3$

To determine the coordinate that satisfies the inequality, let us substitute the coordinates in both of the inequalities $y>-x+1$ and $$y$

Thus, we have,

Option A: $(1,-1)$

Substituting the coordinates in $y>-x+1$ and $y\leq 2 x+3$ , we get,

$y>-x+1\implies-1>0$ is not true.

$$y\leq 2 x+3 \implies -1\leq 5$ is true.

Since, only one equation satisfies the condition, the coordinate $(1,-1)$ is not a solution.

Hence, Option A is not the correct answer.

Option B: $(-4,0)$

Substituting the coordinates in $y>-x+1$ and $y\leq 2 x+3$ , we get,

$y>-x+1\implies0>5$ is not true.

$$y\leq 2 x+3 \implies 0\leq -5$ is not true.

Since, both the equations does not satisfy the condition, the coordinate $(-4,0)$ is not a solution.

Hence, Option B is not the correct answer.

Option C: $(3,-2)$

Substituting the coordinates in $y>-x+1$ and $y\leq 2 x+3$ , we get,

$y>-x+1\implies-2>-2$ is not true.

$$y\leq 2 x+3 \implies -2\leq 9$ is true.

Since, only one equation satisfies the condition, the coordinate $(3,-2)$ is not a solution.

Hence, Option C is not the correct answer.

Option D: $(0,3)$

Substituting the coordinates in $y>-x+1$ and $y\leq 2 x+3$ , we get,

$y>-x+1\implies3>1$ is true.

$$y\leq 2 x+3 \implies 3\leq 3$ is true.

Since, both equation satisfies the condition, the coordinate $(0,3)$ is a solution.

Hence, Option D is the correct answer.

4 0

2 years ago

it is not always helpfule to rewrite an equation in standard form as a first step in solving it? true or false

Anni [7]

Answer:

True

Step-by-step explanation:

8 0

3 years ago

Darlene's room measures 12feet on ones side and 9 feet on another, help her calculate the area of her room. The area if a rectan

IrinaK [193]

Answer:

108 ft²

Step-by-step explanation:

The product of length and width is ...

(12 ft)(9 ft) = 12·9 ft·ft = 108 ft²

8 0

3 years ago