A new insecticide is advertised to kill more than 95% roaches upon contact. In a laboratory test, the insecticide was applied to 400 roaches and 384 died immediately after contact. Is this sufficient evidence to support the advertised claim? Use α=0.05. (b) Test statistic for the problem above is
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A new insecticide is advertised to kill more than 95% roaches upon contact. In a laboratory test, the insecticide was applied to 400 roaches and 384 died immediately after contact.
Is this sufficient evidence to support the advertised claim? Use α=0.05.
(b) Test statistic for the problem above is
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- In a test of H0: µ=150 against HA: µ<150, a sample of size 250 produces Z = -0.65 for the value of the test statistic. Thus the p-value is approximately equal toIf I have a sample of 20 people what is my T-threshold for a two-tail test and an alpha of 0.1 percent?A nationwide study of undergraduate students reported that the mean number of drinks consumed per week during the spring semester is 7.96. The mean number of drinks consumed per week at USC is 7.64 (s.d.=2.55, N=412 Health services is concerned that USC students are consuming significantly more alcohol per week than the national average. Using an alpha level of .05, Is there sufficient evidence to be concerned? Be sure to select the correct critical value for the alternative hypothesis, and then use this evidence to make your conclusion
- As we have noted in previous chapters, even a very small effect can be significant if the sample is large enough. Suppose, for example, that a researcher obtains a correlation (computed from the raw data) of r = 0.60 for a sample of n = 10 participants. (4 pts. total) Is this sample sufficient to conclude that a significant correlation exists in the population? Use a two-tailed test with α = .05. In your response, be sure to specify the critical value for r.A survey of 90 recently delivered women on the rolls of a county welfare department revealed that 27 had a history of intrapartum or postpartum infection. Can we conclude that the population proportion with a history of intrapartum or postpartum infection is significantly less than or equal to 0.25? Let alpha = 0.05.A large manufacturing company investigated the service it received from its suppliers and discovered that, in the past, 38% of all material shipments were received late. However, the company recently installed a just-in-time system in which suppliers are linked more closely to the manufacturing process. A random sample of 150 deliveries since the just-in-time system was installed reveals that 33 deliveries were late. If we want to test whether the proportion of late deliveries was reduced signicantly at = 0:10 the null and alternative hypotheses are a. Null hypothesis (H0) b. Alternative hypothesis (HA)
- A researcher obtains t=2.25 for a repeated measures study using a sample of n=10 participants. Based on this t value, what is the correct decision for a two- tail test at .05 and .01 alpha level?A study on the effects of color on easing test anxiety compared anxiety test scores of participants who completed a test printed on either soft yellow paper or harsh green paper. The scores for the 10 participants who completed the yellow and the 10 participants who completed it on the green paper are below (Table 5). Using an alpha level of .05, do participants who use the yellow paper report lower test anxiety than those who wrote it on the harsh green paper? -use formulas not excelThe p-value for the above problem is < 0.0001. Which of the following is a correct conclusion? There is not enough evidence that all of the proportions of European football players who take magnesium in topical, pill, and powder form are the same as reported by the football agency. There is strong evidence that all of the proportions of European football players who take magnesium in topical, pill, and powder form are different than reported by the football agency. There is strong evidence that all of the proportions of European football players who take magnesium in topical, pill, and powder form are the same as reported by the football agency. There is strong evidence that at least one of the proportion of European football players who take magnesium in topical, pill, and powder form is different than reported by the football agency. There is not enough evidence that at least one of the proportion of European football players who take magnesium in topical, pill, and…
- A random sample of 54 students from Cabrillo College are selected from a normal population with mu equal to 20 and sigma equal to 5. After a treatment is administered to the students, the researcher calculated the sample mean to be 21. Is there enough evidence to conclude that the treatment had an effect at the 5% significance level? In step three, can we use the Critical Value Method? (a)Don't know (b)Cannot Determine (c)No (d)YesPrevious research has established that nationwide, for older adults, the average score on the Beck Depression Inventory (BDI-II) is 8.13 with σ = 1.56. A researcher working in a nursing home wants to know if depression levels are different for older adults living in a nursing home compared to older adults nationwide. He takes a random sample of 200 adults living in a nursing home facility and gives them each the BDI-II. The average for his sample is 8.45. Is there a difference in the BDI-II scores of those living in a nursing home compared to those living in their own homes? Test with an a = 0.01.What proportions of males and females wear a facemask while in a large parking lot? There is some evidence that the proportion of females wearing facemasks, pf , is different from the proportion of males wearing face masks, pm . We are going to examine this question by randomly selecting n=900 males and m=800 females walking in parking lots and observing how many of the selected people are wearing masks. Let XM equal the number of males in our sample who wear masks. Let XF equal the number of females in our sample who wear masks. Suppose XM = 494 and XF = 494. Let pmhat be the sample proportion of males in our sample who wear masks. Let pfhat be the sample proportion of females in our sample who wear masks. Let pm be the (unknown) true proportion of males who wear masks in large parking lots. Let pf be the (unknown) true proportion of females who wear masks in large parking lots.a)Calculate an unbiased point estimate of pm . b) We wish to construct a 90 % classical confidence…