I need help with this

Ksivusya [100]

-2x^2+8x+5 is the standard form

5 0

3 years ago

An article written for a magazine claims that 78% of the magazine's subscribers report eating healthily the previous day. Suppos

Schach [20]

Answer:

89.44% probability that less than 80% of the sample would report eating healthily the previous day

Step-by-step explanation:

We use the binomial approximation to the normal to solve this question.

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:

$p = 0.78, n = 675$

So

$\mu = E(X) = np = 675*0.78 = 526.5$

$\sigma = \sqrt{V(X)} = \sqrt{np(1-p)} = \sqrt{675*0.78*0.22} = 10.76$

What is the approximate probability that less than 80% of the sample would report eating healthily the previous day?

This is the pvalue of Z when $X = 0.8*675 = 540$ . So

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

$Z = \frac{540 - 526.5}{10.76}$

$Z = 1.25$

$Z = 1.25$ has a pvalue of 0.8944

89.44% probability that less than 80% of the sample would report eating healthily the previous day

8 0

3 years ago

Dale works at a mattress store, and makes a salary plus commission. He has a $500 weekly salary and makes a 5% commission for sa

Anni [7]

Answer:

1. $\( f\circ g(x)=0.05x-150$

2. $\( g\circ f(x)=0.05x-3000$

3. The first one represents Dale's commission

Explanation:

1. The composition of the function

$f\circ g(x)=f(g(x))$

means that you first apply the function g(x) and then f(x) on the output of g(x).

That is:

f(x) = 0.05x
g(x) = x - 3000

$f(g(x)=0.05(x - 3000)$

$f(g(x))=0.05x-150$

2. The composition of the function

$g\circ f(x)=g(f(x))$

means that you first apply the function f(x) and then g(x) on the output of f(x).

That is:

$g(f(x))=((0.05x)-3000)=0.05x-3000$

3. Which one represents Dale's commission

To calculate Dales's commision you must subtract $3,000 from the sales, to find the sales over $3000. That is: x - 3,000, which is the function g(x).

Therefore, you first use g(x).

Then, you must multiply the output of g(x) by 0.05 to find the 5% of the sales over $3,000. That is: 0.05(g((x)) = 0.05(x - 3000) = 0.05x - 150.

Therefore, the composition that represents Dale's commission is the first one:

$f(g(x)=0.05(x - 3000)$

$f(g(x))=0.05x-150$

4 0

2 years ago

H=k/j, for k hellllllllllllllppppppppppp

ss7ja [257]

I'm only answering because the app told me i need to help someone before I can ask another question, but I can't help because I don't know what to help you with so

8 0

3 years ago

Read 2 more answers

For the class of 2013's prom Norman's dress shop sold cheaper dresses for $90 each and more expensive dresses for $140 each. The

Tema [17]

Answer:

Number of cheaper dresses sold is 35

Number of expensive dresses sold is 15

Step-by-step explanation:

Given:

Cost of cheaper dresses = $90

Cost of expensive dresses = $140