Find the standard deviation of the below sample data set. Show your work. 3, 2, 1, 2

According to National Safety​ Council, there were​ 13,600,000 soccer players and​ 208,214 injuries were treated in U.S. emergency rooms related to this sport in a particular year. What is the injury rate per​ 1,000 players? Show your work.

The accompanying table shows data for the numbers of pairs of shoes for female (group 1) and male (group 2). We want find the 95% confidence interval of the mean difference in number of pairs of shoes. The StatCrunch output is shown. Assume that the data are from random and independent samples. (1) Interpret the confidence interval in words. (3%) (2) Using the confidence interval, determine whether the true mean numbers of pairs of shoes are significantly different, and if so which group (female or male) has the larger number of pairs of shoes. State the reason to support your answer.  (4%)  

Select a correlation coefficient from the answer choices which matches to each scatter plot A to E.  Answer choices: -0.65 -0.85 1.00 0.01 0.87   Correlation coefficient (r) for scatter plot A is [plotA]. Correlation coefficient (r) for scatter plot B is [plotB]. Correlation coefficient (r) for scatter plot C is [plotC]. Correlation coefficient (r) for scatter plot D is [plotD]. Correlation coefficient (r) for scatter plot E is [plotE].

Which of the following is a reason we can never draw​ cause-and-effect conclusions from observational​ studies? 

Assume that the mean of 1,000 sample newborn infants in the U.S. is 7.2 pounds with a standard deviation of 1.2 pound and the distribution of the weight is symmetric and unimodal. Using the Empirical rule, approximately how many newborn infants in the sample are between 4.8 and 9.6 pounds? Show your work.

EXAM PROBLEM #2 Instructions: Type your answers to the questions in the textbox below. Label your answers A and B. Show all work on your “work” page.  Label which problem it is (#2). Reaction:     4 NH3 (g)  +  5 O2 (g) –>  4 NO (g)  +  6 H2O (g)              ΔH = -906.0 kJ Questions: A.   Is heat released or absorbed by the system in this reaction? Briefly explain how you know. B.   How many grams of ammonia, NH3 must react in order for 53.18 kcal to be released or absorbed in this reaction?    

When computing the correlation​ coefficient, what is the effect of changing the order of the variables on​ r? 

There are 50,000 households in Village V. Of all households in Village, 30% of the households use more than one language. Suppose that we do know this fact and want to estimate the true proportion of households which use more than one language. We take a random sample of 200 households from  all households in Village ensuring the independence of the sample.  Find the standard error of the sampling distribution, and then find the probability that less than 62 households in this sample use more than one language using an appropriate formula and the Normal distribution table shown below. Show your work.

EXAM PROBLEM #5 Instructions: Type your answer to the question in the textbox below. Show all work on your “work” page.   Label which problem it is (#5) Situation: A large bottle contains some boric acid solution with an unknown concentration.  A 25.00 mL sample of this acid solution is titrated with a 1.438 M NaOH solution.  It takes 18.31 mL of the NaOH solution to reach the endpoint of the titration. Reaction:  H3BO3 (aq)  +  3 NaOH (aq)   –>   3 H2O (l)  +  Na3BO3 (aq) Question: What is the molarity of the unknown boric acid solution?