questions 4, 8,9,10

One recent study found that online math and statistics training quizzes worked quite well. The regression equation, y = 86.909 - 4.6545x, expresses statistical dependence of the final grade in statistics (y) on the number of quizzes missed by students (a) in a sample of 11 statistics students. If the coefficient of determination is r = 0.9440, then the coefficient of correlation is O0.972 O-0.902 O-0.972 O-0.938 O-0.966 O0.891 O-0.9440 O-0.927 ONone of the above.Some latest study shows that college students are increasingly skimping on their sleep. A researcher from a small community college wants to estimate the mean weekdays sleep time of its students. He takes a random sample of 90 students and records their weekday mean sleep time as 6.10 hours. Assume that the population standard deviation is fairly stable at 1.10 hours. (a) Construct a 96% confidence interval for the population mean weekday sleep time of all students of this college. Use the following table of za for most common a values. 0.005 0.01 0.02 0.03 0.04 0.05 0.06 0.1 2.575 2.33 2.05 1.88 1.75 1.645 1.555 1.28 2.81 2.575 2.33 2. 17 2.05 1.96 1.88 1.645 Find za = Round the margin of error and confidence interval values to 2 decimal places. Calculate the margin of error E = What is the 96% confidence interval? SUS (b) If the researcher wants to be 97% confident that the sample mean is within 0.30 hours (or 18 min) of the true population mean weekday sleep time, how many students should he include in the sample? Find za = Round your answer (n) UP to the next whole number. The required sample size n is Question Help: Message instructor Add Work > Next Question MacBook AllA complete list of beaty salons in Ontario is compiled and every 65th is selected. This type of sampling is called Ostratified sampling random sampling systematic sampling cluster sampling convenience sampling ONone of the above.In conducting market analysis for a pharmaceutical company, a researcher interviews 35 of its most loyal customers. This type of sampling is called O cluster sampling O systematic sampling O random sampling convenience sampling stratified sampling None of the above