Blog

Prof Rea’s Exam Q7 Suppose that the president has a 54% approval rating among voters. (The population is large enough for trials to be considered independent). What is the probability that a randomly selected voter disapproves of the president? What is the probability that all 4 randomly selected voters approve of the president? Round your answer to three decimal places. What is the probability that of 15 randomly selected voters, exactly 4 approve of the president? Use binomial probability.  Round your answer to three decimal places. Show the calculation to earn full credit.

Prof Rea’s Exam Q8 Given below is a clickable scatterplot generated from data taken from 11 high school students. The LSR line is graphed on the same plane.    Sample mean Sample standard deviation linear correlation coefficient SAT math score (x) 436 160.466 0.976 High school GPA (y) 73.273 14.867 Use the information in the table above to compute the slope and y-intercept of the LSR line. Then write the equation of the LSR line. Round all values to two decimal places. 

Prof Rea’s Exam Q10 The given scatterplot was generated from data for the first two decades of flu reporting.   The LSR line has equation

Prof Rea’s Exam Q5 Given below is a clickable scatterplot generated from data taken from 11 high school students. What does a point on the scatterplot represent?    

Exam Question 7 The following table shows the number of people who developed Covid-19 in a sample of 94 total participants who developed Covid-19. Participants are organized by their reported gender and whether they received a vaccine or placebo in the trial.  Vaccine Placebo Total Male 4 42 46 Female 3 36 39 Other 1 8 9 Total 8 86 94 What is the probability of someone with a vaccine developing Covid-19? To earn full credit, write your answer using probability notation, as a fraction and decimal rounded to three decimal places. What is the probability that someone who is male and vaccinated develops Covid-19? To earn full credit, write your answer using probability notation, as a fraction and decimal rounded to three decimal places. A student answers the following question incorrectly. Explain the mistake they made and answer the question correctly (use proper notation and justify your answer with a calculation).  Question: Is it more likely to meet a man with a placebo that developed Covid-19 or a woman with a placebo that develops Covid-19? Answer: Since there are more men who received the placebo than women, you are more likely to meet a man with a placebo that developed Covid-19. What is the probability that someone who is male or vaccinated develops Covid-19? To earn full credit, write your answer using probability notation, as a fraction and decimal rounded to three decimal places.

Exam Question 5 The two given distributions have the same mean. Without doing any calculations, identify which distribution has less variability. Explain why you think this.  a.   b.

You will now upload your Work and Answer Template here. Change your Work and Answer Template to ONE pdf file and send it to your computer. Click the RED “Start Assignment” button. Click the “Choose File” button and select your file. Click the RED “Submit Assignment” button again. Make sure your file was uploaded successfully (you may see confetti!). Click the button at the bottom of this question where it says “I have successfully uploaded my work and answer template pdf file and am ready to click “Submit Quiz” at the bottom of the page.” Click the “Submit Quiz” button at the bottom of the page to finish/submit this assessment DO NOT CLICK SUBMIT QUIZ UNTIL YOU HAVE SUBMITTED THE ASSIGNMENT AND SEE CONFETTI

Prof Rea’s Exam Q12 A roulette wheel has 18 red numbers, 18 black numbers, and 2 green numbers. So, the proportion of red numbers is 0.474, the proportion of black numbers is 0.474, and the proportion of green numbers is 0.052. The table below gives the frequencies with which the ball landed on each color in 200 trials. Do the results suggest that the wheel is out of balance? Perform a goodness of fit test using a 5% level of significance. Step 1: Form your hypotheses.  Step 2: Calculate the expected frequencies and verify that the criteria for the Chi-Square distribution is satisfied. Color Observed frequency Expected frequency red 84 black 106 green 10 Step 3: Calculate the test statistic. Round each term to four decimal places. Use the test statistic to find the P-value rounded to four decimal places. You may use this desmos graph to compute the P-value. Step 4: State the conclusion in the context of the problem.

1. This assessment is enabling you to demonstrate your understanding elementary statistics. Use techniques you have learned to solve all problems on the assessment. Points will be earned primarily through the process of solving. Therefore, you will show as much work as possible and will provide justification whenever necessary. Use models, tables, and/or write descriptively when providing explanations. Write your favorite topic from the class in the left-hand bottom corner of the first page. Write something down, even if you don’t know the final answer. The solutions you provide should be of your own original thought. No collaboration/discussion with anyone is permitted or use of any computer system or server, is allowed. Desmos is permitted on this assessment. Please write the desmos function used if you do. If I suspect any part of the work is not your own, you will earn a zero on the assessment and the activity will be reported to the college to be formally processed and permanently recorded. Sign your name on your work and answer template to acknowledge and agree to these terms. 

Prof Rea’s Exam Question 3. Show as much work as possible and clearly show all five steps of building a confidence interval to earn credit: You wonder how much time, on average, people are spending on social media. You randomly survey 150 adults in the US and find that they spend an average of 180 minutes on social media per day. You compute the sample standard deviation to be 40 minutes. Construct and interpret a 95% confidence interval for the mean time (in minutes) that adults in the US spend on social media. Round all calculated values to three decimal places.