Phosphorous is a chemical that is found in many household cleaning products. Unfortunately, phosphorous also finds its way into surface water, where it can harm fish, reduction (mg/L) was recorded. Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value a small amount and thereby produce a slightly more "conservative" answer. Site Method I: Method II: 4 0.007 0.017 0.013 0.020 0.015 0.017 0.002 0.001 0.010 0.013 0.039 0.014 Do these data indicate a difference (either way) in the average reduction of phosphorous between the two methods? Use a 0.05. (Let d = Method I - Method II.)

Wisconsin ACT math II This plot shows the mean ACTscores for Wisconsin schools with the Milwaukee schoolsremoved. The vertical lines show the mean, mean - 1s,and mean + 1s. a) Describe the shape of the distribution.b) Does a normal model seem appropriate for thisdistribution?c) 68.9% of the school average scores are between thetwo outer lines. Does that support or refute youranswer to part b? d) Below, a normal model with mean 21.910 and stan-dard deviation 1.539 is drawn over the histogram. Explain how this demonstrates George Box’s statement,“All models are wrong—but some are useful.”

How do the sample mean and the population mean differ? What is the symbol for each type of mean?

What's the Z score and how is it calculated?

260 300 340 The distribution is normal. The locations of the peak and inflection points are shown.

3. New car price and used (1 year old) car price for the same model (thousands of dollars): Model A Model B Model CModel D Model E New price X 47.8 32.1 33.4 36.1 44.5 Used (1 year) 42.2 price Y 29.8 31.1 32.0 42.3 a. Using Excel find the value of the correlation coefficient. 34.091 V38.9656 Ans, e. Using the work sheet on the next page and an a = .01, test the claim that p> 0, there is a correlation between new price and used price. TESTING: Random Variable: Special considerations/characteristics: Given: Question:

Stephanie is trying to figure out the sample size of an experiment. She knows the population SD is 41.5 and the SD of the sample averages is 2.7. What is the sample size of the experiment?

A professor believes that his math students have different IQ than the average college students. He collected the IQ scores of 30 students in his class. Then, he compared it to the average IQ score of college students. Provided below is the data that the professor gathered.Sample:Mean: 103 Std. Dev: 7 N: 30 Population: Mean: 100 Std. Dev: 5 A). What is the type of test you will use? (z-test, single-sample t-test, paired-samples t-test, or independent samples t-test) and why (what information provided in the problem) B). What are the hypotheses (Be Specific)

What is the value of the sample test statistic? (Round your answer to three decimal places.)

​Claim: Fewer than 94​% of adults have a cell phone. In a reputable poll of 1150 ​adults, 85​% said that they have a cell phone. Find the value of the test statistic The value of the test statistic is