Question

A psychologist wants to compare three methods for reducing hostility levels in university students. Eleven students...

A psychologist wants to compare three methods for reducing hostility levels in university students. Eleven students were judged to have "great hostility," based on a certain psychological test (HLT). These students were then randomly divided into three groups—five were treated by Method A, three were treated by Method B, and the other three students were treated by Method C. All treatments continued throughout a semester, at the end of which the HLT test was given again. The results are shown in the table.

Method Scores on the HLT Test
A 75 83 74 68 81
B 55 75 71
C 79 96 86

Let μA and μB, respectively, denote the mean scores for the populations of extremely hostile students who were treated by Methods A and B.

(a) Find a 95% confidence interval for μA. (Round your answers to two decimal places.)

(b)Find a 95% confidence interval for μB.  (Round your answers to two decimal places.)

(c)Find a 95% confidence interval for (μA − μB).  (Round your answers to two decimal places.)

Math   Statistics-And-Probability   
0 0
Add a commentTranscribed image text
Next >

Homework Answers

Answer #1

0 0
Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Log In

Sign Up

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
A clinical psychologist wished to compare three methods for reducing hostility levels in university students using...
A clinical psychologist wished to compare three methods for reducing hostility levels in university students using a certain psychological test (HLT). High scores on this test were taken to indicate great hostility, and 11 students who got high and nearly equal scores were used in the experiment. Five were selected at random from among the 11 students and treated by method A, three were taken at random from the remaining six students and treated by method B, and the other...
A clinical psychologist wished to compare three methods for reducing hostility levels in university students using...
A clinical psychologist wished to compare three methods for reducing hostility levels in university students using a certain psychological test (HLT). High scores on this test were taken to indicate great hostility, and 11 students who got high and nearly equal scores were used in the experiment. Five were selected at random from among the 11 students and treated by method A, three were taken at random from the remaining six students and treated by method B, and the other...
A university financial aid office polled a random sample of 921 male undergraduate students and 961...
A university financial aid office polled a random sample of 921 male undergraduate students and 961 female undergraduate students. Each of the students was asked whether or not they were employed during the previous summer. 599 of the male students and 747 of the female students said that they had worked during the previous summer. Give a 95% confidence interval for the difference between the proportions of male and female students who were employed during the summer. Step 1 of...
A consumer preference study compares the effects of three different bottle designs (A, B, and C)...
A consumer preference study compares the effects of three different bottle designs (A, B, and C) on sales of a popular fabric softener. A completely randomized design is employed. Specifically, 15 supermarkets of equal sales potential are selected, and 5 of these supermarkets are randomly assigned to each bottle design. The number of bottles sold in 24 hours at each supermarket is recorded. The data obtained are displayed in the following table. Bottle Design Study Data A B C 19...
Suppose the preliteracy scores of three-year-old students in the United States are normally distributed. Shelia, a...
Suppose the preliteracy scores of three-year-old students in the United States are normally distributed. Shelia, a preschool teacher, wants to estimate the mean score on preliteracy tests for the population of three-year-olds. She draws a simple random sample of 20 students from her class of three-year-olds and records their preliteracy scores (in points). 74,79,83,85,88,90,94,95,95,97,99,99,100,103,105,105,106,107,107,108 Calculate the sample mean (?⎯⎯⎯x¯), sample standard deviation (?s), and standard error (SE) of the students' scores. Round your answers to four decimal places. Determine the...
A university financial aid office polled a random sample of 467 male undergraduate students and 574...
A university financial aid office polled a random sample of 467 male undergraduate students and 574 female undergraduate students. Each of the students was asked whether or not they were employed during the previous summer. 270 of the male students and 290 of the female students said that they had worked during the previous summer. Give a 90% confidence interval for the difference between the proportions of male and female students who were employed during the summer. Step 1 of...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that IQ scores follow a normal distribution. Her random sample of 25 IQ scores has a mean of 97.4 and a standard deviation of 17.2. Find the 99% confidence interval for the population standard deviation based on this sample. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places. (If necessary,...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that...
A psychologist wants to estimate the standard deviation of IQ scores. It is widely believed that IQ scores follow a normal distribution. Her random sample of 25 IQ scores has a mean of 99 and a standard deviation of 13.2 . Find the 99% confidence interval for the population standard deviation based on this sample. Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to at least two decimal places. (If...
A university financial aid office polled a random sample of 751 male undergraduate students and 810...
A university financial aid office polled a random sample of 751 male undergraduate students and 810 female undergraduate students. Each of the students was asked whether or not they were employed during the previous summer. 472 of the male students and 588 of the female students said that they had worked during the previous summer. Give a 80% confidence interval for the difference between the proportions of male and female students who were employed during the summer. Step 1 of...
A university financial aid office polled a random sample of 937 male undergraduate students and 993...
A university financial aid office polled a random sample of 937 male undergraduate students and 993 female undergraduate students. Each of the students was asked whether or not they were employed during the previous summer. 382 of the male students and 528 of the female students said that they had worked during the previous summer. Give a 90% confidence interval for the difference between the proportions of male and female students who were employed during the summer. Step 1 of...
ADVERTISEMENT
Need Online Homework Help?

Get Answers For Free
Most questions answered within 1 hours.

Ask a Question
ADVERTISEMENT