Mathematics > QUESTIONS & ANSWERS > MATH221A Lesson 21- Homework Quiz (All)

MATH221A Lesson 21- Homework Quiz

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Lesson 21: Homework Quiz Question 1 1 / 1 pts If the correlation coefficient (r) is positive, when one variable decreases, the other variable: stays the same. Question 2 1 / 1 pts Data was collected on homes for sale in Madison County as of January 2011. Information on the listings such as price, size of the home, and style were recorded. The data are recorded in MadisonCountyRealEstate.xlsx (Links to an external site.)Links to an external site.. Create a scatterplot of the price of homes (ListPrice) compared with how old the homes are (Age). Select the answer that best describes the data illustrated in the scatterplot. Question 3 1 / 1 pts Use the following information to answer the next 2 questions. Researchers studying healthy body composition recorded various measurements of 252 male subjects. Height, weight, age, and other measurements were collected on each subject. The data are recorded in BodyMeasurementsCorrected.xlsx (Links to an external site.)Links to an external site. For this exercise, we will look at the height of the subjects compared with the weight. Compute the sample correlation coefficient of the height compared with the weight. Give your answer accurate to three decimal places. (Example: Question 4 1 / 1 pts Create a scatterplot using these two variables. Using this scatterplot and referring to the correlation coefficient above, select the answer that best describes the data illustrated in the scatterplot. Question 5 1 / 1 pts The entrance rate into a prestigious university's graduate program is 13%. A statistics student wants to know if the entrance rate of applicants from BYU-Idaho is greater than the typical entrance rate. He decides to conduct a hypothesis test of one proportion to determine whether the entrance rate of BYU-Idaho students into the graduate program is higher than 13%. He randomly selects 60 students who have applied and records whether or not each student was admitted. Were the requirements for the hypothesis test met? Explain. Question 6 1 / 1 pts A factory makes components used in jet engines, including reinforced steel washers. The washers are required to have a very precise thickness. The thickness of the washers follow a normal distribution with mean 1.59 millimeters and standard deviation 0.042 millimeters. A technician randomly samples n=20 washers and calculates the mean of their thicknesses, which is x¯. What is the probability that x¯<1.57? Question 7 1 / 1 pts Use the following information to answer the next 3 questions. Parents of children with developmental disorders can apply for federal funding, to help pay for psychosocial rehabilitation. A sociologist working for the annual Current Population Survey wants to know the percentage of applicants for this funding who are in poverty. She needs a sample of applicants from across the U.S., so she groups all of the applications by state and randomly selects applicants from each state. What sampling scheme did she use? Stratified sampling Question 8 1 / 1 pts She calculates the percentage of applicants in her sample that are in poverty. Is this percentage a parameter or a statistic, and why? Question 9 1 / 1 pts What was the population being studied? Quiz Score: 9 out of 9

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