<span>11.2 Florida voters. Florida played a key role in the 2000 and 2004 presidential elections. Voter
registration records in August 2010 show that 41% of Florida voters are registered as Democrats
and 36% as Republicans. (Most of the others did not choose a party.) To test a random digit
dialing device that you plan to use to poll voters for the 2010 Senate elections, you use it to call
250 randomly chosen residential telephones in Florida. Of the registered voters contacted, 34%
are registered Democrats. Is each of the boldface numbers a parameter or a statistic?
Answer
41 % of registered voters are Democrats: parameter
36% of registered voters are Republicans: parameter
34% of voters contacted are Democrats: statistic
11.7 Generating a sampling distribution. Let’s illustrate the idea of a sampling distribution in
the case of a very small sample from a very small population. The population is the scores of 10
students on an exam:
The parameter of interest is the mean score ÎĽ in this population. The sample is an SRS of size n =
4 drawn from the population. Because the students are labeled 0 to 9, a single random digit from
Table B chooses one student for the sample.
(a) Find the mean of the 10 scores in the population. This is the population mean ÎĽ.
(b) Use the first digits in row 116 of Table B to draw an SRS of size 4 from this population.
What are the four scores in your sample? What is their mean ? This statistic is an estimate of
ÎĽ.
(c) Repeat this process 9 more times, using the first digits in rows 117 to 125 of Table B. Make a
histogram of the 10 values of . You are constructing the sampling distribution of . Is the
center of your histogram close to ÎĽ?
Answer
(a) ÎĽ = 694/10 = 69.4.
(b) The table below shows the results for line 116. Note that we need to choose 5 digits because
the digit 4 appears twice.
(c) The results for the other lines are in the table; the histogram is shown after the table.</span>
Answer:
Stimulation of thoracic or lumbar spinal regions; impulse reaches chain ganglion; acetylcholine release
Explanation:
Answer:
2
Explanation:
that is what evolution says
Answer:
You did not write the concept, so i will try to answer in a general way.
Why sometimes we really need to model concepts?
Well, sometimes the things are really complicated, or we just do not have the knowledge or tools to fully understand them.
Here is where the models came to be handy, we can somewhat "simplify" the things, and explain them with models.
For example, the movement of a particle as the wind pushes it can be really complex, so this can only be explained with a model.
Now, once we have a model (supported by theory and experiments) we can start to investigating furthermore in the given subject.
So for example, we could model how a given therapy acts on a given disease, and with that model, we could extrapolate the effects of the therapy in a similar disease (for example, testing how radiotherapy acts on a given tumor in some organ, can give information on how the same therapy can act on other types of tumors)
Concluding, models simplify some concepts, which allow us to understand them and work better with them
