Let x denote the time (in minutes) that it takes a fifth-grade student to read a certain passage. Suppose that the mean value and standard deviation of x are μ = 4 minutes and a = 0.8 minutes, respectively. (a) If x is the sample mean time for a random sample of n = 9 students, where is the x distribution centered, and how much does it spread out around the center (as described by its standard deviation)? (Round your answers to three decimal places.) minutes minutes 0x (b) Repeat part (a) for a sample of size of n = 60 and again for a sample of size n = 100. (Round your answers to three decimal places.) n = 60 4x = 07 = minutes minutes n = 100 fx 0x = How do the centers and spreads of the three x distributions compare to one another? The centers of the distributions of the sample mean are --Select-- distributions are ---Select-- minutes minutes , and the standard deviations (and therefore spreads) of these

In a normal distribution, x = 5 and z = –1.4. This tells you that x = 5 is ____ standard deviations to the ____ (right orleft) of the mean.

Suppose a population is known to be normally distributed with a mean, µ, equal to 116 and a standard deviation, ơ, equal to 14. Approximately what percent of the population would be between 130 and 144? 68% 47.5% 95% 81.5% 34% 13.5%

In an independent groups experiment, group A’s mean is 220 and group B’s mean is 180. The estimated population standard deviation is 12, and the standard error of the distribution of differences between means is 20.  What is the t obtained value?       2.0       3.33       20       10.00

Suppos are interested in studying a population to estimate its mean. The population is normal and has a standard deviation of G=23. We have taken a random sample of size 11=95 from the population. This is Sample 1 in the table below. (In the table, Sample 1 is written "S1", Sample 2 is written "S2", etc.) As shown in the table, the sample mean of Sample 1 is = 142.0. Also shown are the lower and upper limits of the 80% confidence interval for the population mean using this sample, as well as the lower and upper limits of the 95% confidence interval. Suppose that the true mean of the population is = 140, which is shown on the displays for the confidence intervals. Press the "Generate Samples" button to simulate taking 19 more random samples of size 11 = 95 from this same population. (The 80% and 95% confidence intervals for all of the samples are shown in the table and graphed.) Then complete parts (a) through (c) below the table. 80% 80% 95% 95% lower upper lower upper limit limit…

Q1.2 Standard Deviation of Sampling Distribution of x-bar Suppose the distribution of cholesterol levels in a population of men is approximately normally distributed with a mean of 200 mg/dL and a standard deviation of 32 mg/dL. What is the standard deviation of the sampling distribution of for n=25? Write your answer as a decimal value rounded to four decimal places. (Don't put any text or supporting work! Just the numeric value.)

Suppose a population is known to be normally distributed with a mean, μ, equal to 116 and a standard deviation, σ, equal to 14. Approximately what percent of the population would be between 116 and 130? 1. 47.5% 2. 34.% 3. 68% 4. 81.5% 5. 13.5 6. 95%

Suppose a population is known to be normally distributed with a mean, μ, equal to 116 and a standard deviation, σ, equal to 14. Approximately what percent of the population would be between 102 and 144? 1. 13.5% 2. 34% 3. 47.5% 4. 95% 5. 68% 6. 81.5%