a. Increasing df tends to make the t-distribution more similar to a normal distribution.b. Increasing df typically results in a larger critical t-value.c. Decreasing df often results in a more conservative interpretation of the results.d. Decreasing df would require larger calculated t-values to reject the null hypothesis. How does changing the degrees of freedom (df) in a t-test affect the outcome?

How the changing of degrees of freedom in any t-test affect the outcome from the given options must…

Answered: How does changing the degrees of…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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using Excel: The General Manager has heard a rumor that the employees with a “low” salary are working more hours (on average) than the employees with a “high” salary. The manager asks you to find out if the difference in average working hours is significantly more on the “low” salary employees than on the “high” salary employees. Use a t-test please explain on excel. State the null and alternative hypothesis and Show the summary output (No need to show it just explain how and which intercepts to select using EXCEL) Satisfaction Level 2020 Satisfaction Level 2019 number_project average_montly_hours time_spend_company Work_accident promotion_last_5years position salary 0.41 0.46 2 128 3 0 0 accounting low 0.38 0.5 2 132 3 0 0
True or False? A clinical trial is conducted to compare an experimental medication to placebo to reduce the symptoms of asthma. One hundred participants are enrolled in the study and randomized to receive either the experimental medication or placebo. The primary outcome is self-reported reduction of symptoms. Among 50 participants who receive the experimental medication, 30 report a reduction of symptoms as compared to 15 participants of 50 assigned to the placebo. The 95% CI for the relative risk of participants reporting a reduction of symptoms between the experimental and placebo groups is between 0.114 and 0.486.
Impact of College Roommates on Grades In this exercise, we investigate answers to the questions: How much of an effect does your roommate have on your grades? In particular, does it matter whether your roommate brings a videogame to college? A study was conducted involving n = 210 first-year students who were randomly assigned a roommate. Table 1 gives summary statistics on grade point average (GPA) for the first semester depending on whether the student and/or the roommate brought a videogame to campus. Student brought videogame No The 90% confidence interval is i Yes No Yes Roommate brought videogame No No Yes Yes Sample size Mean GPA 88 44 38 40 3.128 ! to i 3.039 2.932 2.754 St. Dev. 0.590 0.689 0.699 Table 1 Videogames and GPA Considering only students who do not bring a videogame to campus, find a 90% confidence interval for the difference in mean GPA between students whose roommate does not bring a videogame and those whose roommate does bring a videogame μN - μy, where μN…
A survey conducted on a group of 250 people randomly recruited from among the retirees revealed that 115 people were willing to find a new job. It is known that the rate of those who previously wanted to work among retired people is 67%. Can it be claimed that the ratio of these two tendencies is different from each other for the 2% significance level? Test it, interpret the decision you made as a result of the test. While testing the hypothesis test, apply the 4 stages and show them separately.
2
Standardized test scores For his Statistics class experi-ment, researcher J. Gilbert decided to study how parents’ income affects children’s performance on standardizedtests like the SAT. He proposed to collect informationfrom a random sample of test takers and examine therelationship between parental income and SAT score.a) Is this an experiment? If not, what kind of study is it?b) If there is relationship between parental incomeand SAT score, why can’t we conclude that differencesin score are caused by differences in parentalincome?
Automation refers to the use of strategies & tools which augment or reduce the need ofmanual or human involvement in unskilled, repetitive or redundant tasks.Give three (3) benefits of automated testing.
A biopsychologist studies the role of the brain chemical serotonin in aggression. One sample of rats serves as a control group and receives a placebo. A second sample of rats receives a drug that lowers brain levels of serotonin. Then the researcher tests the animals by recording the number of aggressive responses each of the rats display. (Hint: Be sure to use the correct test statistic). Low Serotonin Control n = 4 n = 8 M = 22 M = 14 SS = 76 SS = 164 Does the drug have a significant effect on aggression? Use an alpha level of .05, two tails. Be sure to state your conclusion. Use Cohen’s d to measure the effect size. What is the size of effect?
Impact of College Roommates on Grades In this exercise, we investigate answers to the questions: How much of an effect does your roommate have on your grades? In particular, does it matter whether your roommate brings a videogame to college? A study was conducted involving n = 210 first-year students who were randomly assigned a roommate. Table 1 gives summary statistics on grade point average (GPA) for the first semester depending on whether the student and/or the roommate brought a videogame to campus. Student brought videogame No Yes No Yes Roommate brought videogame No No Yes Yes Sample size 88 44 38 40 Mean GPA 3.128 3.039 2.932 2.754 Table 1 Videogames and GPA St. Dev. 0.590 0.689 0.699 0.639 Considering only students whose roommate does not bring a videogame to campus, find a 99% confidence interval for the difference in mean GPA between students who bring a videogame and those who do not bring a videogame μN - My, where μ represents the mean GPA for students who do not bring a…
Part 2 of 5 (b) Compute the value of the test statistic. Round the answer to two decimal places. t =
6(5)
MORE BENEFITS OF EATING ORGANIC Using specific data, we find a significant difference in the proportion of fruit flies surviving after 13 days between those eating organic potatoes and those eating conventional (not organic) potatoes. This exercise asks you to conduct a hypothesis test using additional data. In this case, we are testing where p, and p, represent the proportion of fruit flies alive at the end of the given time frame of those eating organic food and those eating conventional food, respectively. Use a 5 % significance level. Effect of Organic Soybeans After 5 Days After 5 days, the proportion of fruit flies eating organic soybeans still alive is 0.9, while the proportion still alive eating conventional soybeans is 0.83. The standard error for the difference in proportions is 0.023. What is the value of the test statistic? Round your answer to two decimal places. What is the p-value? Round your answer to three decimal places. p-value= i ! What is the conclusion? Ho: Po Pe…

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