First Questions. These questions should be answered on your own. They should be turned in separately.
1) One set of data is roughly N(20, 2). the other set of data is roughly N(20,5). Compare and contrast these two sets of data.
2) Data is roughly N(12, 4).
between what two numbers (roughly) is the middle 95% of the data?
the middle 99.7% ?
3) What steps should we do to ensure that our data is roughly normal?
4) IQ scores for adults are roughly N(100,15). What percent of adults have an IQ below 80?
5) attached is the growth of an icicle (in cm) over time (in minutes). Find the line of best fit, the correlation, and tell me how long the icicle would be after 240 minutes.
***you do not need to make fancy graphs for this****
6) What does the regression plot tell us about bivariate data, and when should we use it?
7) Does a high chi-square total for a cell in our table tell us the value is higher than our expected value? Explain.
8) What is changes occur to our hypothesis testing when we use an alpha of 0.10 as opposed to 0.05?
***please make sure to give me more than "one is a 95% confidence and the other is a 90% confidence"***
9) A liquid made for insulating connections in electronics is supposed to have a specific resistance. We test it five times and get the following readings:
5.32 4.88 5.10 4.73 5.15 4.75
The liquid is supposed to have a conductivity of 5, with a standard deviation of 0.2. run a hypothesis test to determine whether or not this sample of the fluid is acceptable. Make sure to consider whether or not it is one-tailed, two-tailed, etc. don't worry about removing any of the points--with so few points we aren't worried about possible outliers.
*****
Longer form questions.
These questions are going to be phrased a little differently than you are used to. Instead of me asking for all of the information specifically, at this point you should be able to tell ME what information is important. You should be able to pick the important pieces, work with them, and give me results back. So don't think that because there aren't 10 parts that there isn't a lot of work to be done.
...there is.
Question One:
Nitrogen in Diamonds.
A sample of diamonds is tested for the amount of nitrogen in them. This helps scientists figure out how they were created. Below is the data--give me a 95% confidence interval for what you think the average nitrogen content is. (the numbers below are parts per million):
487 1430 60 244 196 274 41 54 473 30 98 41 273 94 69 262 120 302 75 242 115 65 311 61
You are not given the true population standard deviation, so use the sample standard deviation instead
Question Two:
Aleppo Pine needles (cm):
10.2 7.2 7.6 9.3 12.1 10.9 9.4 11.3 8.5 8.5 12.8 8.7 9.0 9.0 9.4
Torrey Pine needles (cm):
33.7 21.2 26.8 29.7 21.6 21.7 33.7 32.5 23.1 23.7 30.2 29.0 24.2 25.5 26.6 28.9 29.7
Summarize numerically and make a graphic that shows the difference in the lengths of the two trees. If I handed you five needles of the following lengths, which type of tree do you think they would belong to?
12.4
6.1
17.3
33
Question Three:
A statistics professor at a large university believes that the students take an average of 15 credit hours per term. He samples 24 students in his class. We do not know the sd of the population, so use the sd of the class. Here are the results:
12 13 14 14 15 15 15 16 16 16 16 16 17 17 17 18 18 18 18 19 19 19 20 21
Analyze the data, and see whether or not the professors claim is reasonable. Include both a hypothesis test and a confidence interval. At the end of the question, include any possible biases or problems with the data collection.
Question Four:
Come up with some specific, numerical claim about BBA.
for example:
the average student spends 30 minutes doing homework an evening.
students who drive to school live an average of 10 miles away from school
freshman have better GPAs than seniors.
In order to test your claim, what would you need to do? What steps, precautions, and other general information would you need to acuire? Outline a process by which would would gain the information needed to do test your claim of BBA.