Math Answers

A course in Physics was taught to 10 students using the traditional method Another group of 11 students went through the same course using another method. At the end of the semester, the same test was administered to each group. The 10 students under method A got an average of 82 with a standard deviation of 5, while the 11 students

under method B got an average of 78 with a standard deviation of 6. Test the null hypothesis of no significant difference in the performance of the two groups of students at 5% level of significance

Find the variance and standard deviation of the probability distribution of a random variable x which can take only the values 1,5,3,7,9 and 2 given that P(1) = 1/14 , P(5) = 2/14, P(3) = 4/14, P(7) = 3/14, P(9) = 1/14, P(2) = 3/14.

Find the variance and standard deviation of the probability distribution of a random variable x which can take only the values 1,2,3,4 and 5, given that P(1) = 3/10, P(2) = 1/10, P(3) = 2/10, P(4) = 3/10, P(5) = 1/10.

Consider a population consisting of 3, 6, 7, 9, 10, 4, and 8. Suppose samples of size 2 are drawn from this population. Describe the sampling distribution of sample means. What is the standard deviation of the sampling distribution? NOTE: EXPRESS YOUR ANSWER INTO 4 DECIMAL PLACE VALUES

It is known that cellular phones batteries by a certain factory have lifetimes that follow a normal distribution. The average lifetime of the batteries is known to be 2.4 years. A random sample size of 16 will be taken.

1. Determine the mean and the standard error of the sampling distribution of the means.

2. What is the distribution of the sampling distribution of the sample mean?

3. What is the probability that a random sample size of 16 will have a sample mean greater than 2.5 years?

4. What is the probability that a random sample of size 16 will have a sample mean of less than 2.2 years?

Given the population: 1, 3, 4, 6, and 8; and suppose samples of size 3 are drawn from this population:

1. What is the mean and standard deviation of the population?

2. How many different samples of size n=3 can be drawn from the population? List them with their corresponding means

3. Construct the sampling distribution of the sample means.

4. What is the mean of the sampling distribution of the sample means?

5. What is the standard deviation of the sampling distribution of the sample means?

Given population 15, 12, 6, 9, and 17. Suppose samples of size 3 are drawn from this population. Complete the table and draw the sketch of histogram. Describe the distribution

In particularly community,it is claimed that the mean household water usage for a particular month is 48 cubic meters. The following year,a country wide water conservation campaign was conducted.Forty five homes were randomly selected and found that the mean comsumption is 52 cubic meters with a standard deviation of 4 cubic meters.Is there enough evidence to say that the mean household water usage per month is higher than 48 cubic meters at a=0.01?

An academic organization claimed that Grade 11 students study time is at most 200 minutes per day, on average. Another survey was conducted to find whether the claim is true. The group took a random sample of 30 students and found a mean study time of 240 minutes with standard deviation of 100 minutes.

Answer the following:

Parameter:

Claim:

Claim ( in symbol ):

Ho: Ho:

Ha: Ha:

What is the significance level or a?

Is it two-tailed or one-tailed test?

2. A researcher claims that the average salary of a private school teacher is greater than P20,000 with a standard deviation of P5,000. A sample of 20 teachers has a mean salary of P25,000. Test the claim of the researcher. At 0.05 level of significance, test the claim of the researcher.

Answer the following:

Parameter:

Claim:

Claim ( in symbol ):

Ho: Ho:

Ha: Ha:

What is the significance level or a?

Is it two-tailed or one-tailed test?