Perform Tests for Means.
Week 9 – Assignment: Perform t tests for Means
Instructions
For this task, write a paper using the following structure:
Begin with a one or two-paragraph introduction that summarizes the meaning of the reading material.
Answer all of the questions included in Parts 1 and 2 below. Be sure to answer questions using complete sentences and show all work in your calculations.
Provide a written conclusion, when appropriate, for the problem that you are addressing.
Include an essay section in your paper, which is described in Part 3 below.
Use the last part of your paper to include a paragraph or two that explains the information that you learned in the assignment. Support your paper with at least two references.
Part 1
Explain how the t distribution is similar to a normal distribution, and how it difference from a normal distribution.
Explain the differences in terms of the null hypothesis between a one-sample t test, a two sample t test, and a matched pairs t test.
Suppose that you are testing the null hypothesis H0: µ = 100 against Ha: µ < 100 based on a random sample of nine observations from a normal population. The data from the sample give a mean of 98 and a standard deviation of 3. What is the value of the t statistic?
In Problem 3, either find the exact p-value or determine a lower and upper bound of the p-value for the test statistic.
Identify the correct type of t test to use in the following situations. Choose from a 1-sample, 2-sample, or matched pairs t test.
a) You interview 500 female students and ask each about the average number of minutes they spend using the internet each day.
b) You interview a sample of 250 unmarried male students and 250 unmarried female students and ask each about the average number of minutes they spend using the internet each day.
c) You interview 200 female students in their freshman year and again in their senior year and ask each about the average number of minutes they spend using the Internet each day.
Explain how the degrees of freedom are determined using:
a) a one sample t test
b) a two sample t test
A marketing company believes that younger adults use social media more than adults aged 35 or over. To investigate this, the company is planning to take a random sample of each group and determine the sample means.
a) Determine which type of statistical test is appropriate.
b) Create the appropriate null and alternate hypothesis for this test.
Part 2
A random sample of 25 U.S. adults were asked to estimate the average income of all U.S. households. The estimate mean was $47,000 with a standard deviation of $15,000. Construct a 95% confidence interval for this data.
People claim that women say more words per day than men. Estimates claim that a woman uses roughly 20,000 words per day, while a man uses approximately 7,000. To investigate this, a researcher recorded conversations of male college students over a 5-day period. The results are as follows:
7220 13932 4727 10419
9258 9717 10728 5265
12215 9944 7979 12252