Answer: Atoms were created after the Big Bang 13.7 billion years ago. As the hot, dense new universe cooled, conditions became suitable for quarks and electrons to form. Quarks came together to form protons and neutrons, and these particles combined into nuclei.
Answer:
A wildfire is an unplanned fire that burns in a natural area such as a forest, grassland, or prairie. Wildfires are often caused by human activity or a natural phenomenon such as lightning, and they can happen at any time or anywhere. In 50% of wildfires recorded, it is not known how they started.
Only autotrophs can convert solar energy into chemical energy
<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>
