Assume that the sample is a simple random sample obtained from a normally distributed population of flight delays at an airport. Use the table below to find the minimum sample size needed to be 95% confident that the sample standard deviation is within 5% of the population standard deviation. A histogram of a sample of those arrival delays suggests that the distribution is skewed, not normal. How does the distribution affect the sample size? To be 95% confident that s is within of the value of o, the sample size n should be at least To be 99% confident that s is 1% 5% 10% 20% 30% 40% 50% 19.205 768 48 192 21 12 8 1% 5% 10% 20% 30% 40% 50% within lof the value of g, the sample size In should be at least 33,218 1,336 336 85 38 22 14 The minimum sample size needed is A histogram of a sample of those arrival delays suggests that the distribution is skewed, not normal. How does the distribution affect the sample size? O A. The computed minimum sample size is not likely correct. O B. The computed sample size should be divided by 2. O C. The computed sample size should be multiplied by 2. O D. The computed minimum sample size is likely correct.

I need help finding the test statistic and the P-value

A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1458 and the standard deviation was 312. The test scores of four students selected at random are 1860, 1220, 2150, and 1340. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1860 is (Round to two decimal plaes as needed.)

P3. Show that the mle of unknown standard deviation when the mean is known is different from the sample standard deviation when the random sample is taken from a normal population characterized by two parameters, mean and variance. Which estimator is unbiased? Justify your answer. Show that a sample mean is a minimum variance unbiased estimator of the mean of a normal population with known variance.

If we meet these conditions, the sampling distribution of the mean will have a normal shape and ... The mean of the sampling distribution will be u, (i.e., the same as the population mean) and the standard deviation of the sampling distribution will be (that's the population standard deviation divided by the square root of the sample size). In the AP Stats Guy video, he talks about the number of text messages his students send during class. Suppose the average number of text messages his students send during class is u = 30 text messages. If we take samples of say, n = 36 students at a time, we would expect the mean of the sampling distribution we create to be the same as the population mean, 30 text messages. If we can further say that standard deviation of the number of text messages is 12 text messages, by how much would we expect the sample means to vary? (hint, use the formula above) text messages

The salaries of professional baseball players are heavily skewed right with a mean of $3.2 million and a standard deviation of $2 million. The salaries of professional football players are also heavily skewed right with a mean of $1.9 million and a standard deviation of $1.5 million. A random sample of 40 baseball players’ salaries and 35 football players’ salaries is selected. The mean salary is determined for both samples. Let  represent the difference in the mean salaries for baseball and football players. Which of the following represents the shape of the sampling distribution for ? skewed right since the populations are both right skewed skewed right since the differences in salaries cannot be negative approximately Normal since both sample sizes are greater than 30 approximately Normal since the sum of the sample sizes is greater than 30

The lengths of pregnancies in a small rural village are normally distributed with a mean of 267 days and a standard deviation of 15 days.In what range would you expect to find the middle 95% of most pregnancies?Between  and .If you were to draw samples of size 55 from this population, in what range would you expect to find the middle 95% of most averages for the lengths of pregnancies in the sample?Between  and .

The salaries of professional baseball players are heavily skewed right with a mean of $3.2 million and a standard deviation of $2 million. The salaries of professional football players are also heavily skewed right with a mean of $1.9 million and a standard deviation of $1.5 million. A random sample of 40 baseball players' salaries and 35 football players' salaries is selected. The mean salary is determined for both samples. Let -T, represent the difference in the mean salaries for baseball and football players. Which of the following represents the standard deviation of the sampling distribution for - -- ? O 0.41 million O 0,57 million Save and Exit Next Submit Mark this and return hp & 4 6. 7 8. 9. y h k