Correct Answer highlighted without Calculations



Discrete Components Inc. manufactures a line of electrical resistors. Presently, the carbon composition line is producing 100 ohm resistors. The population variance of these resistors “must not exceed 4” to conform to industry standards. Periodically, the quality control inspectors check for conformity by randomly select 10 resistors from the line, and calculating the sample variance. The last sample had a variance of 4.36. Assume that the population is normally distributed.
increase the sample size
reduce the sample size
reject the null hypothesis
do not reject the null hypothesis

Independent random samples selected from two normal populations produced the sample means and standard deviations shown below:

(-5.64, 0.04)
(-4.13, -1.47)
(-5.19, -0.41)
(-6.18, 0.58)

A researcher wants to estimate the difference in population proportions for two populations using a 98% confidence interval. In a sample of 900 persons from the first population, 288 possessed the characteristic of interest. In a sample of 800 from the second population, 240 possessed the characteristic of interest. A 98% confidence interval for the difference in the population proportions is ___.
{0.0323, -0.0723}
{0.0423, 0.0723}
{0.0223, 0.0923}
{-0.0323, 0.0723}
{0.0323, 0.0723}

Restaurateur Denny Valentine is evaluating two sites, Raymondville and Rosenberg, for his next restaurant. He wants to prove that Raymondville residents (population 1) dine out more often than Rosenberg residents (population 2). Denny commissions a market survey to test this hypothesis. The market researcher used a random sample of 64 families from each suburb, and reported the following: x1= 16 times per month and x2= 14 times per month. Assume that σ1 = 4 and σ2 = 3. With α = .01, the appropriate decision is ___.
reject the null hypothesis σ1 < σ2 accept the alternate hypothesis μ1 – μ2 > 0
reject the alternate hypothesis n1 = n2 = 64
do not reject the null hypothesis μ1 – μ2 = 0

A researcher wants to conduct a before/after study on 11 subjects to determine if a treatment results in any difference in scores. The null hypothesis is that the average difference is zero while the alternative hypothesis is that the average difference is not zero. Scores are obtained on the subjects both before and after the treatment. After subtracting the after scores from the before scores, the average difference is computed to be 2.40 with a sample standard deviation of 1.21. Assume that the differences are normally distributed in the population. The observed t value for this test is ___.

A researcher is conducting a matched-pairs study. She gathers data on each pair in the study resulting in:

Assume that the data are normally distributed in the population. The degrees of freedom in this problem are ___.
The answer is 4


The dean of a business school claims that the average starting salary of its graduates is more than 60 ($thousands). It is known that the population standard deviation is 10 ($thousands). Sample data on the starting salaries of 64 randomly selected recent graduates yielded a mean of 62 ($thousands). What is the value of the sample test statistic?2.001.801. 851.651.60

Descriptive Writing and Grammar Review



Descriptive Writing and Grammar Review
1. Read the “The Secret Power of Things We Hold Dear” (2007) by Sherry Turkle (search for this online or in the EBSCO database).
2. Read Writing Elements: A Quick Guide to Grammar and Usage (2012) by Goss and Goss (find this in this week’s readings or in the Course Resources folder located under the Lessons tab).
3. Read and respond to each of the following writing prompts. Submit them as a single document.
Part 1: Descriptive Writing
In her 2007 article, “The Secret Power of Things We Hold Dear,” Sherry Turkle discusses the importance of objects on a personal level. She describes her weekends spent at her grandparents’ apartment in Brooklyn, looking through the items that her grandparents saved, and using the information she gleaned from these items, gains a deeper understanding of her mother and her aunt. In her article, Turkle explains that the items that she looked at again and again “had a high emotional intensity” because they made her think about the father she never met (Turkle, 2007, para. 6). In this sense, Turkle uses the art of bricolage (“do-it-yourself”) to piece together who her father was.
For this writing assignment, use bricolage to describe a person close to you or someone you know very well: What objects surround this person? What does his or her physical space (living space, work space, or other) look like? How does he or she dress? Describe this person’s physical appearance as well as any mannerisms, gestures, or expressions he or she uses. Show this person doing something that he or she would do on a regular basis. The idea is to create a dominant impression of this person by selecting key details, as you did in your discussion this week.
Write a one-paragraph (five to seven sentences) physical description of this person and his or her surroundings using specific sensory details so the reader can visualize this person. Write a second paragraph discussing what you think these objects, environment, appearance, and so forth say about this person. Practice ways of showing your reader the significance rather than telling the reader of its importance.
Turkle, S. (2007). The secret power of things we hold dear. New scientist, 194(2607), 50-52.
Part 2: Grammar Review
In Writing Elements (2012), Goss and Goss briefly explore the most common grammar and usage issues found in student writing. Read through the guide and find three areas where you struggle or have struggled with your own writing. Write an example of each of these issues and demonstrate a way each issue can be corrected.
For example:
Verb Tense
“I asked her what is her problem.” Incorrect because it uses both past and present tense verbs in the same sentence. This is also an awkward sounding sentence.
“I asked her what her problem was.” Correct (past tense).
Or, “I ask her what her problem is.” Correct (present tense).References
Goss, T. P., & Goss, S. M. (2012). Writing elements: A quick guide to grammar and usage. Kansas City, MO: Grantham University.
Turkle, S. (2007). The secret power of things we hold dear. New scientist, 194(2607), 50-52.


Confidence interval



Consider the formula used for any confidence interval and the elements included in that formula. What happens to the confidence interval if you

. increase the confidence level,

. increase the sample size, or

. increase the margin of error?

Only consider one of these changes at a time. Explain your answer with words and by referencing the formula.




32% of college students say they use credit cards because of the rewards program. You randomly select 10 college students and ask each to name the reason he or she uses credit cards. Find the probability that the number of college students who say they use credit cards because of the rewards program is​ (a) exactly​ two, (b) more than​ two, and​ (c) between two and five inclusive. If​ convenient, use technology to find the probabilities.