In a population, the mean is known to be 1.27 and the standard deviation is known to be 0.351. Suppose a random sample of size 169 is taken from this population. What can be said about the distribution of the sample mean? Select one: It is approximately normal with mean 1.27, but the standard deviation is not known.

The average salary for a certain profession is ​$80,000. Assume that the standard deviation of such salaries is ​$27,500. Consider a random sample of 50 people in this profession and let x represent the mean salary for the sample.

A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1471 and the standard deviation was 318. The test scores of four students selected at random are 1910, 1210, 2210, and 1370. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1910 is (Round to two decimal places as needed.)

The amounts of electricity bills for all households in a particular city have an approximately normal distribution with a mean of $135 and a standard deviation of $25. Let I be the mean amount of electricity bills for a random sample of 24 households selected from this city. Find the mean and standard deviation of

A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1474 and the standard deviation was 319. The test scores of four students selected at random are 1880, 1190, 2210, and 1380. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The Z-score for 1880 is (Round to two decimal places as needed.) The Z-score for 1190 is (Round to two decimal places as needed.) The z-score for 2210 is (Round to two decimal places as needed.) The z-score for 1380 is (Round to two decimal places as needed.) Which values, if any, are unusual? Select the correct choice below and, if necessary, fill in the answer box within your choice. OA. The unusual value(s) is/are (Use a comma to separate answers as needed.) RECH OB. None of the values are unusual.

Suppose x has a distribution with a mean of 13.9 and a standard deviation of 2.1. Random samples of size n=49 are drawn. What would be the mean and standard deviation of the x̄ distribution?

Alex wants to find out: if the standard deviation of the mean for the sampling distribution of random samples of size 256 from a large or infinite population is 9, how large must the sample size become if the standard deviation is to be reduced to 2.7 (or even smaller)?

Two normal distributions are compared. One has a mean of 10 and a standard deviation of 10. The second normal distribution has a mean of 10 and a standard deviation of 2. Which of the following is true? The dispersions of the distributions are different. The dispersions of the distributions are the same. The distributions are from two different families of distributions. The locations of the distributions are different.

For the population of one town, the number of siblings, x, is a random variable whose relative frequency histogram has a reverse J-shape. The mean number of siblings is 1.3 and the standard deviation is 1.5. Let x denote the mean number of siblings for a random sample of size 32. Determine whether the distribution of x is normal or approximately normal and find its mean and standard deviation.

Use z scores to compare the given values. The tallest living man at one time had a height of 238 cm. The shortest living man at that time had a height of 142.4 cm. Heights of men at that time had a mean of 175.45 cm and a standard deviation of 5.59 cm. Which of these two men had the height that was more extreme? ... Since the z score for the tallest man is z = 0 and the z score for the shortest man is z = the man had the height that was Im- more extreme. (Round to two decimal places.) shortest tallest