TRY IT 4.1 A hospital researcher is interested in the number of times the average post-op patient will ring the nurse during a 12- hour shift. For a random sample of 50 patients, the following information was obtained. Let X = the number of times a patient rings the nurse during a 12-hour shift. For this exercise, x = 0, 1, 2, 3, 4, 5. P(x) = the probability that X takes on value x. Why is this a discrete probability distribution function (two reasons)? P(x) 4 P(x = 0) 50 8 P(x = 1) = 50 1 16 2 P(x = 2) = 50 14 P(x = 3) = 50 4 6 P(x = 4) = 50 5 P(x = 5) = 50 Table 4.3

A psychologist found a study which claiming that 32% of patients who visit a psychologist have symptoms of anxiety. This psychologist had 44 patients visit. Let x = the number of patients that had symptoms of anxiety. (a) The random variable is which of the following? O the number of psychologists O the number of patients who visited the psychologist the number of patients who had symptoms of anxiety O the number of patients without symptoms of anxiety (b) How many total patients did the psychologist have visit?

Suppose that 75%75% of college students prefer pepperoni on their pizzas. You took a sample of ?=150n=150 at your college and found that 70%70% said they want pepperoni on their pizzas. You want to know if your college is different from the rest at the 10%10% level. What is the ?P‑value for this test?

Bighorn sheep are beautiful wild animals found throughout the western United States. Let x be the age of a bighorn sheep (in years), and let y be the mortality rate (percent that die) for this age group. For example, x = 1, y = 14 means that 14% of the bighorn sheep between 1 and 2 years old died. A random sample of Arizona bighorn sheep gave the following information: x 1 2 3 4 5 y 15.8 17.3 14.4 19.6 20.0   Σx = 15; Σy = 87.1; Σx2 = 55; Σy2 = 1,540.45; Σxy = 272 (a) Find x, y, b, and the equation of the least-squares line. (Round your answers for x and y to two decimal places. Round your least-squares estimates to three decimal places.) x =  y =  b =  ŷ =  +  x (b) Draw a scatter diagram for the data. Plot the least-squares line on your scatter diagram.         (c) Find the sample correlation coefficient r and the coefficient of determination r2. (Round your answers to three decimal places.) r =   r2 =   What percentage of variation in y is…

In a computer instant messaging survey, respondents were asked to choose the most fun way to flirt, and it found that P(D) = 0.750, where D is directly in person. If someone is randomly selected, what does P (D) represent, and what is its value? What does P (D represent? O A. P(D) is the probability of randomly selecting someone who did not participate in the survey. B. P(D) is the probability of randomly selecting someone who chooses a direct in-person encounter as the most fun way to flirt. C. P(D) is the probability of randomly selecting someone who did not have a preference in regards to the most fun way to flirt. D. P(D) is the probability of randomly selecting someone who does not choose a direct in-person encounter as the most fun way to flirt.

Bighorn sheep are beautiful wild animals found throughout the western United States. Let x be the age of a bighorn sheep (in years), and let y be the mortality rate (percent that die) for this age group. For example, x = 1, y = 14 means that 14% of the bighorn sheep between 1 and 2 years old died. A random sample of Arizona bighorn sheep gave the following information: x 1 2 3 4 5 y 15.8 17.3 14.4 19.6 20.0   Σx = 15; Σy = 87.1; Σx2 = 55; Σy2 = 1,540.45; Σxy = 272 (a) Find x, y, b, and the equation of the least-squares line. (Round your answers for x and y to two decimal places. Round your least-squares estimates to three decimal places.) x =   y =   b =   ŷ =   +   x

Suppose that a college determines the following distribution for X = number of courses taken by a full-time student this semester: Value of X 3 Probability 0.07 4 5 6 0.25 0.28 The probability for X = 4 is missing. What is it? 0.07 0.25 0.40 0.50

A sunscreen company is attempting to improve upon their formula so that it lasts in water longer. They have 4 lead scientists who each came up with a different formulas. In order to see if there is a difference in the time the sunscreen lasts the CEO collects a random sample of each of the four sunscreens the data is shown below. Test the claim that at least one sunscreen has a different lifespan in water at a 0.10 level of significance. Sunscreen A Sunscreen B Sunscreen C Sunscreen D 84 33 31 71 75 66 31 78 57 72 43 63 64 77 64 89 43 52 46 84 76 34 61 45 The hypotheses for this ANOVA test would be: Η 0: μ Αμ Bμ c μ D HA : At least one mean is different. (claim) 0.10 Complete the ANOVA table below: (round answers to 3 decimal places) df MS F p-value Between Within The decision of the test is to: reject Ho do not reject H0