How much do students pay, on the average, for textbooks during the first semester of college? From a random sample of 400 students the mean cost was found to be $357.75, and the sample standard deviation was $37.89. Assuming that the population is normally distributed, find the margin of error of a 95% confidence interval for the population mean.
Answer to relevant QuestionsThere is concern about the speed of automobiles traveling over a particular stretch of highway. For a random sample of 28 automobiles, radar indicated the following speeds, in miles per hour: Assuming a normal population ...Find the margin of error to estimate the population proportion for each of the following. a. n = 350; p` = 0.30; α = 0.01 b. n = 275; p` = 0.45; α = 0.05 c. n = 500; p` = 0.05; α = 0.10 From a random sample of 400 registered voters in one city, 320 indicated that they would vote in favor of a proposed policy in an upcoming election. a. Calculate the LCL for a 98% confidence interval estimate for the ...Consider the following random sample from a normal population: 12 16 8 10 9 a. Find the 90% confidence interval for population variance. b. Find the 95% confidence interval for the population variance. Assume simple random sampling. Calculate the 95% confidence interval estimate for the population mean for each of the following. a. N = 1200; n = 80; s = 10; x = 142 b. N = 1425; n = 90; s2 = 64; x = 232.4 c. N = 3200; n = ...
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