Help plz plz plz i need help

First photo question-The graph below shows three different normal distributions.

zheka24 [161]

Answer:

For the first question: They must each have a different mean and a different standard deviation. For the second question: In an observational study the researchers do not control treatment and in an experiment they do. For the third question: The second graph. For the fourth question: The second graph.

Step-by-step explanation:

For the first question: We can see that each bell-shaped curve is centered around a different number. This tells us that their means are all different.

We can also see that each curve has a different width; this means that the spread of data, measured in part by the standard deviation, is different as well. This means both the mean and the standard deviation of each distribution is different.

For the second question: In an observational study, as the name implies, all that is done is observation. There is no treatment given by the researchers. In an experiment, however, one group receives treatment and one group does not, so the differences can be measured.

For the third question: In the first graph, the probabilities add up to 1.2. This is more than 100%, so this is not a valid distribution. In the second graph, the probabilities add up to 1.0; this is 100% exactly, so this is a valid distribution.

For the fourth question: In the first graph, the probabilities only add up to 0.9. This is not 100%, so this is not a valid distribution. In the second graph, the probabilities add up to 1.0; this is 100% exactly, so this is a valid distribution.

8 0

3 years ago

Read 2 more answers

Rlly need help pls hurry fast

Serjik [45]

Answer:

Angles 7 and 8 are supplementary because they are a pair of adjacent angles that form a straight line.

Supplementary angles add up to 180°

8 0

3 years ago

In 2008 the Better Business Bureau settled 75% of complaints they received (USA Today, March 2, 2009). Suppose you have been hir

Anton [14]

Answer:

Explained below.

Step-by-step explanation:

According to the Central limit theorem, if from an unknown population large samples of sizes n > 30, are selected and the sample proportion for each sample is computed then the sampling distribution of sample proportion follows a Normal distribution.

The mean of this sampling distribution of sample proportion is:

$\mu_{\hat p}= p$

The standard deviation of this sampling distribution of sample proportion is:

$\sigma_{\hat p}=\sqrt{\frac{p(1-p)}{n}}$

(a)

The sample selected is of size n = 450 > 30.

Then according to the central limit theorem the sampling distribution of sample proportion is normally distributed.

The mean and standard deviation are:

$\mu_{\hat p}=p=0.75\\\\\sigma_{\hat p}=\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.75(1-0.75)}{450}}=0.0204$

So, the sampling distribution of sample proportion is $\hat p\sim N(0.75,0.0204^{2})$ .

(b)

Compute the probability that the sample proportion will be within 0.04 of the population proportion as follows:

$P(p-0.04$

$=P(-1.96$

Thus, the probability that the sample proportion will be within 0.04 of the population proportion is 0.95.

(c)

The sample selected is of size n = 200 > 30.

Then according to the central limit theorem the sampling distribution of sample proportion is normally distributed.

The mean and standard deviation are:

$\mu_{\hat p}=p=0.75\\\\\sigma_{\hat p}=\sqrt{\frac{p(1-p)}{n}}=\sqrt{\frac{0.75(1-0.75)}{200}}=0.0306$

So, the sampling distribution of sample proportion is $\hat p\sim N(0.75,0.0306^{2})$ .

(d)

Compute the probability that the sample proportion will be within 0.04 of the population proportion as follows:

$P(p-0.04$

$=P(-1.31$

Thus, the probability that the sample proportion will be within 0.04 of the population proportion is 0.81.

(e)

The probability that the sample proportion will be within 0.04 of the population proportion if the sample size is 450 is 0.95.

And the probability that the sample proportion will be within 0.04 of the population proportion if the sample size is 200 is 0.81.

So, there is a gain in precision on increasing the sample size.

6 0

3 years ago

Solve each problem #1.

Elza [17]

15% = 15/100 = 15 out of a hundred. You answer is fifteen.

4 0

3 years ago

If the force on a rope is 60 N and its mass is 0.12, then the acceleration of the rope is.....

aev [14]

Answer is 7.2 m/s^2
Explanation: acceleration formula is a=Fm therefore 60x0.12=7.2

4 0

2 years ago