Researchers are interested in the effect of pet companionship on depression in elderly adults. They randomly select 25 participants from the target population and record theirdepression scores before and after spending a month with a dog (a higher score indicates a higher level of depression). The researchers then compute the difference scoresfor each participant (difference = after before). The mean of differences is -1 and the standard deviation of differences is 2. Can the researchers conclude that there is aneffect of pet companionship on depression in elderly adults? Conduct the appropriate statistical test (two-tailed) with a = .05.The 95% Confidence Interval for the population parameter is:[-6.16, 4.16][-3.50, 1.50][-1.83,-.17][-3.06, 1.06]

Sample size (n) = 225Sample mean (x̅) = --1Standard deviations (s) = 2Confidence level (c) = 95% =…

Answered: Researchers are interested in the…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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Researchers are interested in the effect of pet companionship on depression in elderly adults. They randomly select 25 participants from the target population and record their depression scores before and after spending a month with a dog (a higher score indicates a higher level of depression). The researchers then compute the difference scores for each participant (difference after before). The mean of differences is - 1 and the standard deviation of differences is 2. Can the researchers conclude that there is an effect of pet companionship on depression in elderly adults? Conduct the appropriate statistical test (two-tailed) with a = .05. Based on the information provided above, which statistical test seems most appropriate? one sample t test O z test independent samples t test O dependent samples t test
In the current pandemic situation, customers are making greater use of grocery home delivery services. A local grocery chain wants to know how satisfied customers in Fairfax county are, on average, with their home delivery service. It surveyed 42 customers in Fairfax county and asked them to rate their satisfaction on a 100-point scale. They obtained a sample average of 82 points. This service has been provided by the grocery chain for some time and the population standard deviation of satisfaction is known to be 6.5 points. What is the population for which inferencing is being done? (narrative, no calculation) What is the population parameter for which inferencing is being done? (narrative, no calculation) At a 97% level of confidence, what is the margin of error? What is the 97% confidence interval for the population parameter? [Note: be sure to express the confidence interval in narrative form for the context of this problem.]
Researchers conducted a study to determine the effects of different types of alcohol on the peak alcohol concentration. In one part of the study, the researchers gave 15 randomly select males a controlled volume of vodka and monitored the subjects' alcohol concentration following the period of consumption. The legal limit for driving is 80 mg/dL (milligrams per deciliter of blood). A hypothesis test was conducted to see if the mean peak alcohol concentration from drinking vodka was different from the legal driving limit. This was reflected in the null and alternative hypotheses ?0:??1:?=80 mg/dL≠80 mg/dL The researchers required their results to be statistically significant at a level of ?=0.10. The mean peak alcohol concentration of the participants after drinking a controlled volume of vodka was 77.4 mg/dL with a standard deviation of 17.25 mg/dL. Determine the confidence interval that corresponds to the ?‑test. Give the lower and upper bounds precise to two decimal places
After post-graduate study, Mike found a job as HR analyst in London. The company is currently recruiting Chief Marketing Officer. The HR department recently sent out a knowledge test to the applicants after the initial CV screening. At this stage of selection, the company does not invite the lowest scoring 30% back for the next face-to-face interview. According to the historical data, the test scores on this test are normally distributed and has a mean of 70 with standard deviation of 10. What mark (to the nearest whole number) must a candidate achieve in order to secure an interview? 2. How much is the 95% confidence interval for the test scores?
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We are trying whether, a new low fat diet actually helps obese people lose weight. 100 randomly obese people are assigned to group 1 and put on a low fat-diet. another 100 people are assigned to group 2 and put on a diet of approximately the same amount of food, but not as low in fat. After 4 months, the mean net weight loss was 9.31 pounds for group 1 with a standard deviation of 4.67 pounds, and for group 2 the mean net weight loss was 7.40 pounds with a standard deviation of 4.04 pounds. Is the low-fat diet more effective? Perform a hypothesis test at the 5% significance level a) Define Parameters and state null and alternative hypothesis b) Find test statistics c) Find p-value d) Conclusion
Researchers are interested in the effect of pet companionship on depression in elderly adults. They randomly select 25 participants from the target population and record their depression scores before and after spending a month with a dog (a higher score indicates a higher level of depression). The researchers then compute the difference scores for each participant (difference after before). The mean of differences is -1 and the standard deviation of differences is 2. Can the researchers conclude that there is an effect of pet companionship on depression in elderly adults? Conduct the appropriate statistical test (two-tailed) with a = .05. Should you reject or fail to reject the null hypothesis? Reject O Fail to reject
A graduate student is interested in how viewing different types of scenes affects working memory. For his study, he selects a random sample of 36 adults. The subjects complete a series of working memory tests before and after walking in an urban setting. Before the walk, the mean score on the test of working memory was 9.1. After the walk, the mean score was 1.4 higher. The graduate student has no presupposed assumptions about how viewing different types of scenes affects working memory, so he formulates the null and alternative hypotheses as: H00 : μDD = 0 H11 : μDD ≠ 0 Assume that the data satisfy all of the required assumptions for a repeated-measures t test. The graduate student calculates the following statistics for his hypothesis test: Mean difference (MDD) 1.4 Estimated population standard deviation of the differences (s) 1.6 Estimated standard error of the mean differences (sMDMD) 0.2667 Degrees of freedom (df) 35 The t statistic 5.25 The critical values of t…
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An English teacher has been teaching a sixth grade composition class for many years. He has the feeling that over the past several years, the writing ability of students has changed. A national test of proficiency in composition was administered 5 years ago. The resulting distribution of scores was normally shaped, had a mean of 85 and a standard deviation of 10.9. In order to test his feeling, he gives his present class of 43 students the same proficiency test. The resulting mean is 80 and the standard deviation is 8.7. a. What is the alternative hypothesis? b. What is the null hypothesis? c. What is your conclusion, using á = 0.052 tail? d. What type error may you be making because of your conclusion in part c?
Part 1 of 4 Suppose that you randomly survey death records for people born in 1900 in Virginia and compared the life span of two different ethnicities. Of the 132 individuals sampled from ethnicity 1, the mean life span was 58.5 years with a standard deviation of 16.9 years. Of the 191 individuals sampled from ethnicity 2, the mean life span was 54.3 years with a standard deviation of 10.3 years. Conduct a hypothesis test with a 7% level of significance to see if the mean life spans in Virginia were the same for the two ethnicities. Step 1: State the null and alternative hypotheses. Ho: 12V✓0 Ha: 1₂V0 (So we will be performing a two-tailed Part 2 of 4 Step 2: Assuming the null hypothesis is true, determine the features of the distribution of the differences of sample means. The differences of sample means are t-distributed and distribution standard deviation Question Help: Post to forum C Submit Part test.) 06 ✓✓with distribution mean MacBook Pro Search or type URL ...........
A researcher is studying psychological factors in artistic achievement among teenage girls. One variable he is particularly interested in is perseverance. What information does a measure of variability for the variable perseverance convey? Check all that apply. What is the central tendency for the variable perseverance among teenage girls? What is the most common value for the variable perseverance among teenage girls? How spread out are the values for perseverance amoung teenage girls? Do all teenage girls have the same amount of perseverance?

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