In a study conducted at Virginia Tech, the plasma ascorbic acid levels of pregnant women were compared for smokers versus nonsmokers. Thirty women in the last three months of pregnancy, free of major healthdisorders and ranging in age from 15 to 32 years, were selected for the study. Prior to the collection of 20 ml of blood, the participants were told to avoid breakfast, forgo their vitamin supplements, and avoid foodshigh in ascorbic acid content. From the blood samples, the accompanying plasma ascorbic acid values were determined, in milligrams per 100 milliliters. Is there sufficient evidence to conclude that there is adifference between plasma ascorbic acid levels of smokers and nonsmokers? Assume that the two sets of data came from normal populations with unequal variances. Use a P-value.Click the icon to view the plasma ascorbic acid values.Let sample 1 be the nonsmokers and let sample 2 be the smokers. State the null and alternative hypotheses.Hoi Hi-H2 = 0(Type integers or decimals. Do not round.)Find the test statistic.The test statistic is -0.70. (Round to two decimal places as needed.)Find the P-value.The P-value is (Round to three decimal places as needed.)

To find the P-value for the given test statistic, you need to use a t-distribution because the…

Answered: In a study conducted at Virginia Tech,…

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 the same anti-venom study, answer the following questions. A study was done on children (6 months to 18 years of age) who had (nonlethal) scorpion stings. Researchers wanted to know the effectiveness of a new anti-venonm. Each child was randomly assigned to receive a shot of the anti-venom or a placebo shot. Researchers recorded whether or not their condition improved over the next four hours. a. Identify the population for the study. b. Identify the sample for the study. (HINT: See #1) c. Was this an observational study or a controlled experiment? Explain how you know. d. Assuming the rest of the study was well-designed, use your answers to discuss whether it would be reasonable to conclude that the new anti-venom is effective at treating nonlethal scorpion stings in children. For the toolbar, press ALT+F10 (PC) or ALT+FN+F10 (Mac). TTTTParagraph Arial 3 (12pt) 三,三,T. 回i:公 E=E= = T T, U HTML CSS O Mashups
A county environmental agency suspects that the fish in a particular polluted lake have elevated mercury levels. To confirm that suspicion, five striped basses in that lake were caught and their tissues were tested for mercury. For the purpose of comparison, four striped basses in an unpolluted lake were also caught and tested. The fish tissue mercury levels in mg/kg are given below. Sample I(From Polluted Lake) 0.523 0.723 0.523 0.623 0.523 Sample II(From Unpolluted Lake) 0.323 0.223 0.523 0.323 0.000 (a) Construct the 95% confidence interval for the difference in the population means based on these data. (b) Test, at the 5% level of significance, whether the data provide sufficient evidence to conclude that fish in the polluted lake have elevated levels of mercury in their tissue.
The average total dollar purchase at a convenience store is less than that at a supermarket. Despite smaller-ticket purchases, convenience stores can still be profitable because of the size of operation, volume of business, and the markup. A researcher is interested in estimating the average purchase amount for convenience stores in suburban Long Island. To do so, she randomly sampled 24 purchases from several convenience stores in suburban Long Island and tabulated the amounts to the nearest dollar (shown below). $9 $7 $1 $2 $14 $11 $7 $8 $6 $7 $3 $3 $2 $5 $4 $4 $1 $2 $3 $10 $8 $8 $6 $4 Assume that the population standard deviation is 3.23 and the population is normally distributed. Using the above data, a 90% confidence interval for the population average amount of purchases is 4.54 to 6.71 4.495 to 6.76 4.44 to 6.81 4.49 to 6.76 4.26 to 6.99
A report summarizing scores for students on a verbal aptitude test x and a math aptitude test y gives the following results: x = 480, sx = 80, y = 500, sy = 120, r = 0.6.
A pharmaceutical company tested the impact of four cholesterol-reducing medications (denoted A, B, C and D) on people at high risk of heart attack. For this clinical trial 20 volunteers with LDL (bad) cholesterol levels of 140 mg/dl were randomly assigned to one of the four medications. The subjects were instructed to take one tablet per day for a period of three months after which their LDL levels were again measured. Below are the amounts (in mg/dl) by which the LDL levels decreased after the three month trial. Medication A Medication B Medication C Medication D 29 31 30 31 30.5 30 32 31.5 30.5 32 31.75 35 31 29.75 27 33 29 31.5 33 29 (d) What assumptions are needed to make this test valid? (e) If a key assumption in (d) is not satisfied, test if the data provide sufficient ev- idence to indicate that at least one of the medications produces a mean reduc- tion in LDL cholesterol that is different from any of the other medications using a non-parametric method (show all working and…
A group of disabled women ages 65 and older were followed for several years. It was found that those who had a vitamin B12 deficiency were twice as likely to suffer from severe depressions than those who did not.a. Describe the type of study being performed.b. Describe the explanatory variable(s) and response variable(s).
Healthy men aged 21 to 35 were randomly assigned to one of two groups: half received 0.82 grams of alcohol per kilogram of body weight; half received a placebo. Participants were then given 30 minutes to read up to 34 pages of Tolstoy’s War and Peace (beginning at chapter 1, with each page containing approximately 22 lines of text). Every two to four minutes participants were prompted to indicate whether they were “zoning out.” The proportion of times participants indicated they were zoning out was recorded for each subject. The table below summarizes data on the proportion of episodes of zoning out (a) What are the two sample standard deviations? (b) What degrees of freedom does the conservative Option 2 use for two-sample t procedures for these samples? (c) Using Option 2, give a 90% confidence interval for the mean difference between the two groups.
A substance abuse counselor wants to demonstrate the effect of situational stress on alcohol cravings. He recruits two groups of men who are similar in respect to history of alcohol use and demographic variables. He divides them in to two groups. In one group(n=11), the men are exposed to a stressful situation and then asked to complete a measure rating their alcohol cravings on a scale from 0-10, where 0 representsno cravings and 10 represents intense cravings. In the second group (n=10), the men are exposed to a neutral situation and asked to complete the same measure. What test and graph should I create to find out if a stressful situation result in more intense alcohol cravings than a non-stressful situation?
The background concentration of a chemical in soil was measured on ten random specimens of soil from an uncontaminated area. The measured concentrations, in mg/kg, are: 1.4, 0.6, 1.2, 1.6, 0.5, 0.7, 0.3, 0.8, 0.2, and 0.9. Soil from a neighboring area will be declared “contaminated” if test specimens contain a chemical concentration higher than the upper 99% confidence limit of the background level. What is the cleanup target concentration?
To examine the effect of relaxing music on math test performance, a researcher wants to compare the average math test scores of participants who completed the test with relaxing music to performance of participants who completed the same math test without music. The partially computed data collected in the study are shown below: Math Test with Music: Math Test without Music: n1 = 16 n2 = 12 M1 = 82 M2 = 78 SS1 = 150 SS2 = 140 Based on these results, is there a significant effect of relaxing music on math test performance? Use a t-test for independent samples with p < .01, 2-tails to answer this research question. Follow the steps of hypothesis testing and insert your answers below. In your calculations, round all numbers to two decimal places to avoid rounding errors. ANSWER H0: H1: Computed pooled variance sp2: Estimated standard SM1 - M2: Computed t: Critical t-value for…
A food-frequency questionnaire is used to measure dietary intake. The respondent specifies the number of servings of various food items they consumed over the previous week. The dietary cholesterol is then quantified for each respondent. The researchers were interested in assessing if there was an association between dietary cholesterol intake and high blood pressure. In a large sample of individuals who had completed the questionnaire, 250 persons with a high dietary cholesterol intake (greater than 300 mg /day) were selected and 250 persons with a low dietary cholesterol intake (less than 300 mg/day) were selected. The 500 selected participants had their medical history taken and were classified as having normal or high blood pressure. The data are given here. Dietary Cholesterol Blood Pressure Total High Low High 159 91 250 Low 78 172 250 Total 237 263 500 Test 2: two-tailed test for comparing two independent proportions Clearly state…
Phosphorous is a chemical that is found in many household cleaning products. Unfortunately, phosphorous also finds its way into surface water, where it can harm fish, plants, and other wildlife. Two methods of phosphorous reduction are being studied. At a random sample of 7 locations, both methods were used and the total phosphorous reduction (mg/L) was recorded. Note: For degrees of freedom d.f. not in the Student's t table, use the closest d.f. that is smaller. In some situations, this choice of d.f. may increase the P-value a small amount and thereby produce a slightly more "conservative" answer. Things that are labelled i underneath a b c, etc are all part of that part.

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