Exam 5: Hypothesis Tests With Means of Samples

A large school district is considering implementing a program that, if successful, would improve the reading scores of its students by 10 points. The current reading scores for the district are normally distributed with a mean of 37 and a standard deviation of 12. The administrators decide to test the new program in one school of 340 students. -What is the standard deviation of the comparison distribution?

Anxiously-attached individuals in the general population tend to have low levels of satisfaction in their romantic relationships (μ = 10, σ = 5, positively skewed distribution). A therapist interested in increasing relationship satisfaction provides a week-long relaxation seminar to 11 anxious individuals. After completing the seminar, relationship satisfaction in the sample averages 12. -What is the corresponding Z score for the sample's mean score on the comparison distribution?

use the following information. One hundred people are included in a study in which they are compared to a known population that has a mean of 73,a standard deviation of 20,and a rectangular distribution. -If the sample mean is 75,the lower limit for the 95% confidence interval is __________.

Supporters of accepting results that reach only "marginal significance" argue that

use the following information. One hundred people are included in a study in which they are compared to a known population that has a mean of 73,a standard deviation of 20,and a rectangular distribution. -If the sample mean is 75,the upper limit for the 95% confidence interval is __________.

The difference between creating a Z score from a single score and creating one from a sample mean is that

A large school district is considering implementing a program that, if successful, would improve the reading scores of its students by 10 points. The current reading scores for the district are normally distributed with a mean of 37 and a standard deviation of 12. The administrators decide to test the new program in one school of 340 students. -What is the shape of the comparison distribution?

The standard deviation of a distribution of means is the square root of the variance of __________.

A large school district is considering implementing a program that, if successful, would improve the reading scores of its students by 10 points. The current reading scores for the district are normally distributed with a mean of 37 and a standard deviation of 12. The administrators decide to test the new program in one school of 340 students. -What is the mean of the comparison distribution?

The comparison distribution when testing a hypothesis involving a sample of more than one participant is a(n)__________.

The comparison distribution for the mean of a sample is the distribution of means because

The mean and variance of a comparison distribution that would be used to test the hypothesis that the mean obtained in a study involving 10 participants is different from a known population having a mean of μ = 100 and σ² = 25 would be

A manufacturer who is considering the implementation of a one-week training program for all new employees decides to test the program with the next 100 employees hired, and then compare their productivity rate to the productivity rate of new employees based on past records—a rate that is normally distributed with a mean of 60 and a standard deviation of 8. The new program needs to produce a minimum improvement of 4 to be considered worthwhile. -What is the mean of the comparison distribution?

A health psychologist knew that corporate executives in general have an average score of 80 with a standard deviation of 12 on a stress inventory and that the scores are normally distributed.In order to learn whether corporate executives who exercise regularly have lower stress scores,the psychologist measured the stress of 20 exercising executives and found them to have a mean score of 72.Is this difference significant at the .05 level? a.Use the five steps of hypothesis testing. b.Sketch the distributions involved. c.Advanced topic: Figure the confidence limits for the 95% confidence interval. d.Explain the logic of what you did to a person who understands hypothesis testing for studies in which the sample consists of a single individual but is unfamiliar with hypothesis testing involving a sample of more than one individual.Be sure your explanation includes a discussion of the distribution of means-what it is,the logic of how it is figured-and its role in the overall hypothesis testing process.Advanced topic: Explain the logic and computation of the confidence intervals.

The first thing that needs to be done to compute the 95% confidence interval is to

Anxiously-attached individuals in the general population tend to have low levels of satisfaction in their romantic relationships (μ = 10, σ = 5, positively skewed distribution). A therapist interested in increasing relationship satisfaction provides a week-long relaxation seminar to 11 anxious individuals. After completing the seminar, relationship satisfaction in the sample averages 12. -What is the shape of the comparison distribution?

The hypothesis testing procedure used when there is a single sample and a known population is a(n)__________.

Dividing the variance of the population of individuals by the number of individuals in each sample yields

When conducting a study involving a sample of several people to see whether they represent a population different from some known population,the __________ is a distribution of means.

An experimental psychologist is interested in whether the color of an animal's surroundings affects learning rate. He tests 16 rats in a box with colorful wallpaper. The average rat (of this strain) can learn to run this type of maze in a box without any special coloring in an average of 25 trials, with a variance of 64, and a normal distribution. The mean number of trials to learn the maze, for the rats tested with the colorful wallpaper, is 11. -What is the null hypothesis?