A random sample of 130 observations produced a mean of x¯¯¯=21.9x¯=21.9 from a population with a normal distribution and a standard deviation σ=3.3. (a) Find a 95% confidence interval for μ       (b) Find a 99% confidence interval for μ       (c) Find a 90% confidence interval for μ

You have taken a random sample of sizen & 95of a normal population that has a population mean ofμ = 140and a population standard deviation ofo = 23. Your sample, which is Sample 1 in the following table, has a mean ofx = 141.3. (In the table, Sample 1 is indicated by "M1", Sample 2 by "M2", and so on.) (to) Based on Sample 1, plot the confidence intervals of80%and95%for the population mean. Use1,282as the critical value for the confidence interval of 80%and use1960 as the critical value for the confidence interval of95%. (If necessary, you can refer to a list of formulas .) • Write the upper limit and the lower limit on the graphs to indicate each confidence interval. Write the answers with one decimal place. • For the points (♦and ◆), write the population mean, μ = 140. 128.0 128.0 80% confidence interval 139.0 X Ś 150.0 150.0 128.0 128.0 95% confidence interval 139.0 X Ś 150.0 150.0

A sample of n=25 scores has a mean of M=68. Find the z-score for this sample: If it was obtained from a population with m=60 and s=10. If it was obtained from a population with m=60 and s=20.   If it was obtained from a population with m=60 and s=40.   A normal distribution has a mean of μ = 54 and a standard deviation of σ = 6. What is the probability of randomly selecting a score less than X = 51? What is the probability of selecting a sample of n = 4 scores with a mean less than M = 51?   What is the probability of selecting a sample of n = 36 scores with a mean less than M = 51?   A sample is selected from a population with a mean of and a standard deviation of . If the sample has scores, what is the expected value of  and the standard error of   If the sample has scores, what is the expected value of  and the standard error of ?   A random sample is obtained from a normal population with a mean of and a standard deviation of . The sample mean is   Is this a…

You have taken a random sample of size n = 12 from a normal population that has a population mean of μ = 90 and a population standard deviation of G = 4. Your sample, which is Sample 1 in the table below, has a mean of x=89.1. (In the table, Sample 1 is written "S1", Sample 2 is written "S2", etc.) (a) Based on Sample 1, graph the 80% and 95% confidence intervals for the population mean. Use 1.282 for the critical value for the 80% confidence interval, and use 1.960 for the critical value for the 95% confidence interval. (If necessary, consult a list of formulas.) • Enter the lower and upper limits on the graphs to show each confidence interval. Write your answers with one decimal place. • For the points (and ◆), enter the population mean, μ = 90. 85.0 S1 |+H 85.0 80% confidence interval 91.0 X +|||||||| x 80% 80% 95% 95% lower upper lower upper limit limit limit limit ? 89.1 ? ? ? S2 90.7 89.2 92.2 88.4 93.0 S3 89.8 88.3 91.3 87.5 92.1 S4 91.9 90.4 S5 89.4 87.9 S6 90.8 89.3 S7 90.6…

A sample of n = 7 scores is selected from a population with an unknown mean ( µ). The sample has a mean of M = 40 and a variance of s 2 = 63. Which of the following is the correct 95% confidence interval for µ?

A person's blood glucose level and diabetes are closely related. Let x be a random variable measured in milligrams of glucose per deciliter (1/10 of a liter) of blood. Suppose that after a 12-hour fast, the random variable x will have a distribution that is approximately normal with mean μ = 88 and standard deviation σ = 21. Note: After 50 years of age, both the mean and standard deviation tend to increase. For an adult (under 50) after a 12-hour fast, find the following probabilities. (Round your answers to four decimal places.) (a) x is more than 60(b) x is less than 110(c) x is between 60 and 110(d) x is greater than 140 (borderline diabetes starts at 140)

A random sample of 130 observations produced a mean of I = 23.5 and a standard deviation s = 2.16. (a) Find a 90% confidence interval for u (b) Find a 95% confidence interval for u (c) Find a 99% confidence interval for u

(b) Let μ1 be the population mean for x1 and let μ2 be the population mean for x2. Find a 95% confidence interval for μ1 − μ2. (Round your answers to two decimal places.) lower limit      % upper limit      %