Statistics and Probability Answers

What are the two things you should do before you start finding the equation of the regression line?

A population consisting of 6 measurements 4 ̧ 5 ̧ 8 ̧ 12 ̧ 9 and 12.

a. Solve for the mean of the population.

b. Solve for the variance of the population.

c. Suppose samples of size 4 are to be taken from this population ̧ what is

the mean of the sampling distribution?

d. What is its variance of the sampling distribution?

e. What is the standard error of the mean?

f. Determine whether the estimate for the population mean is good or bad.

Support your answer.

500 children participated in a field demonstration. Their heights averaged 105 cm with a standard deviation of 5cm. How many children belong to upper 15% of the group.

In a certain Barangay, 550 random residents are chosen in which 225 are males. At a=0.01, test the hypothesis that more than 35% of the Barangay population are male residents.

A researcher wishes to determine the proportion of college students who smoke. He determined that from a sample of 150 college students, 35admitted that they smoke.Is it valid to infer that 23% of college students smoke? Use a = 0.05

Note: Assume that the population is infinite in this case and solve.

Problem: The scores of individual students on a national test have a normal distribution with mean 18.6 and standard deviation 5.9.At Federico Ramos Rural High School, 76 students took the test. If the scores at this school have the same distribution as national scores, what are the mean and standard deviation of the sample means for 76 students.

Table:

Steps Solution

1.Identify the given formation.

2.Find the mean of they sampling distribution. Use the property that Mx=M

3.find the standard deviation of the sampling distribution.

Consider a population consisting of 2,5,6,8, and 10. Suppose samples of size 2 are drawn from this population.

Q1.Compute the mean and the standard deviation of the population.

Q2. List all samples of size 5 and compute the mean for each sample.

Q3. Construct the sampling distribution of the sample means.

Q4. Calculate the mean of the sampling distribution of the sample means.

Q5. Calculate the standard deviation of the sampling distribution of the sample means.

The records of a certain hospital showed that the length of stay of its patients is normally distributed with a mean of 11.5 days and a standard deviation of 2 days. Find the standard score that corresponds to a hospital stay of 9 days.